Chats, Channels & Threads Troubleshooting

“Can't Decrypt” Errors on Messages

Most often, such errors occur because of a temporary network failure: the user's encryption keys temporarily stop syncing between servers or between the client application and the server.

How to Resolve This?

In server software 3.65+ and client applications 3.67+, keys are fixed automatically, so the error may disappear on its own after some time. If the error persists, restart the app on the device where the error appears: on your phone, swipe it from the list of open apps; in the web and desktop apps, press Ctrl (Cmd) + R. You don’t need to end the session.

Nothing Helped?

If the error persists after a restart or repeats on all devices, contact your organization's support or eXpress Support: Support will check and restore your encryption keys. After the keys are restored, restart the app on your phone. In the web and desktop apps, end the session and log back into the app instead of restarting: this removes the old keys from your computer. If you recently reset your password, old messages are encrypted with previous keys and cannot be recovered — more details.

For Administrators: Checking Encryption Keys

CTS

eCTS

Diagnostics

If a user has the “Can't Decrypt” error on all devices or restarting the application did not help, collect diagnostics:

User's HUID	Open the user's active profile in the admin panel, copy the HUID, and send it to eXpress support.
User's keys of type rts from RTS	This information can only be provided by eXpress support.
User's keys of type cts from RTS	This information can only be provided by eXpress support.
User's keys of type cts from CTS / eCTS	Open the user's profile in the CTS / eCTS admin panel, click the Keys button at the top of the screen. Use the search (Ctrl/Cmd + F) for the word “cts” to find keys of type cts. Copy the key ID, issue date, and version number, and send them to support.
Chat JSON of the problematic chat Check the cts_key_id key	Open the user's profile in the CTS / eCTS admin panel, go to the Chats section, find the problematic chat, and click Chat JSON. Copy all the content of the opened page and send it to eXpress support.
Two message_new events (sender and recipient) of the problematic message Check the sender_key_id key	Open the user's profile in the CTS / eCTS admin panel, go to the Chats section, find the problematic chat, and open Events Table. Find an event of type message_new and copy its content. Do not copy the routing_changed event. ⚠️ If the chat is inter-server, request Chat JSON and message_new from each server where this chat exists.

Solution

The key cts with the highest version number and the latest issue date is considered current. If the key is not current, fixing the chat cache (repair) may help. To do this, there is a Restore keys in chats button in the user profile (version 3.23 and later), and below the user list is a Troubleshooting button (version 3.25 and later). Both buttons fix the keys on the current

CTS

/

eCTS

, including for users from another

CTS

/

eCTS

.

If you have been provided with a script that fixes keys, the command Messaging.Troubleshooting.Chats.repair_user("user_huid") from it can be called for multiple users.

“Can't verify” Mark on Messages

The people you're chatting with see the mark, but the error must be fixed on the sender's device: the session keys the app uses to sign their messages have gotten out of sync. That is why everyone they write to sees their messages with this mark.

What the sender should do:

1. Update the app to the current version — Using Updates.
2. Close the session and sign in again: in the web and desktop app — Settings > Close current session, in the mobile app — Settings > Close session. Your chat history will be preserved: after signing in, the app loads the latest messages in each chat you open. If you have created a personal password, the app will ask for it when you sign in.

If the mark remains on new messages, contact your organization's support or eXpress support: they will restore the keys.

Sync Is Stuck: Messages Are Not Sent or Not Visible in One Chat

Error messages may appear: “Updating” or “You can't send messages because you are not a member of this channel anymore.”

How to Resolve This?

Try the following:

• If the chat is a group chat, add a new user to the chat or assign one of the participants as an administrator. This may refresh the chat state and resolve the issue.
• If the chat is personal, create a group chat with the same participants and check if the messages are visible. If the messages are displayed, delete the old personal chat for both participants and recreate it via contacts.
• CTS

  eCTS
  If the problem is related to trusted servers, contact your organization's server administrator through your organization's support or eXpress Support. An example of such a problem: messages are not displayed between users of certain servers in the same organization.

Nothing Helped?

If the described actions do not help, contact your organization's support team or eXpress support for assistance.

For Administrators: Assisting a User with One Problematic Chat

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eCTS

Diagnostics

Most often, the issue arises when the chat has become inactive: for example, after an incorrect user logout or server deletion from

RTS

. To fix a chat, you need its ID. It can be obtained in several ways:

• If the chat is inter-server (cts1+cts2 or rts+cts), and the chat is available in the admin panel on one of the servers, copy its ID from there.
• Inactive chats are hidden in the admin panel. If the chat is on one server and is not displayed in the admin panel, use the web/desktop application:
  • Open Settings > About and click the logo several times to open the engineering menu.
  • Enable the Debug info in the message menu toggle and close the engineering menu.
  • In the problematic chat, right-click any message and select Debug info.
  • In the panel on the right, find the groupChatId value — this is the chat ID.
  If the chat is empty for all participants, make a call in this chat, download the state from any participant's side, and find the groupChatId in it by the participants' HUID.

Inactive chats are not displayed in the chat list in the admin panel, but open via direct address:

• Open any other chat in the admin panel.
• In the browser's address bar, replace the chat ID with the previously obtained groupChatId.
• The desired chat will open with the parameter Active: False.

Solution

If the chat is displayed as inactive in the admin panel, repair the chat using its ID. After the fix, the chat will become active and appear in the admin panel.

Instructions and consultations for fixing a single chat can be obtained from eXpress support.

The command Messaging.Troubleshooting.Chats.resync_chat_servers("chat_ID") in the script from support can be called multiple times with different chat IDs if needed.

If the chat was found in the admin panel, wait for it to sync and load in the client. If the backend version is below 3.7, update it. If the sync does not occur, see the next issue.

Sync Is Stuck: Messages Are Not Sent or Not Visible in All Chats

In all chats, error messages may appear: “Updating” or “You can't send messages because you are not a member of this chat anymore.” Another sign: a corporate user (blue) in the routing of participants of all their chats may be incorrectly displayed as public (green). Yet another sign: the last “online” status of the problematic user may be far in the past, even though they were recently active.

How to Resolve This?

To resolve the issue, it is necessary to fix the chat cache on the corporate server where the error occurred. To do this, contact your organization's Support if the server belongs to it, or contact eXpress Support.

For Administrators: Fixing the Chat Cache

CTS

eCTS

Diagnostics

Check the Conn type value of the user in the admin panel of their home server:

• Open the user's profile in the
  CTS
  /
  eCTS
  admin panel.
• Click the Chats button at the top of the screen.
• Open any chat and click the Users button.
• Find the user in the list and check the Conn type value.

Solution

If Conn type is specified incorrectly (e.g., rts is displayed instead of cts), perform a repair on the user's server.

Instructions and consultations for fixing the chat cache (repair) can be obtained from eXpress support. For repair in the local user profile

CTS

/

eCTS

there is a Restore keys in chats button (version 3.23 and above). For a user from another server, there is a Troubleshooting button under the user list (version 3.25 and above).

The command Messaging.Troubleshooting.Chats.repair_user("HUID_of_the_problematic_user") in the script from support can be called for multiple users if needed.

If the Conn type is correct, and you cannot resolve the issue, collect information on the issues described above and contact eXpress support.

No Messages in Specific Chats on All Devices

Were You Added to a Chat and Can't See the History?

If a member was just now added to the chat, the history may not be visible to them due to end-to-end encryption. If you disable end-to-end encryption, previous messages won't appear: they aren't re-encrypted and remain encrypted with the previous keys.

Can't Even See New Messages, but Notifications Are Coming?

Signs of the issue: messages are missing from one or more group chats, but notifications arrive; the issue occurs on all devices; other participants see the chats normally. In this case, contact Support at your organization so that it can fix your chats.

For Administrators: Fixing the Epoch in a Chat

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eCTS

In backend version 3.10, the chat storage structure was changed: now their history is divided into epochs. The issue is resolved by clearing the end_at value of the epoch.

Diagnostics

Signs of the issue:

• Backend version 3.10 and above.
• Chat history is missing in one or several group chats.
• Occurs on all devices.
• In the epoch query output (see below), there are no epochs with an empty end_at, i.e., all epochs are closed.
• Events are displayed in real time: the sent test message is visible. After re-entering the app or reloading the page, events disappear. At the same time, the event contains a user key.

Additional signs (optional):

• Other participants see the chats normally.
• Push notifications are received.

Solution

Instructions and consultations for fixing the epoch can be obtained from eXpress support.

Unable to Join a Chat by Link, or the Added Participant Is Not in the Chat

Symptoms: error when following an invite link; after being added, the participant cannot be found in the chat participant list; the chat cannot be removed from the list.

What to do?

• Restart the app on the device where the problem occurs.
• If that didn't help, contact Support in your organization or eXpress support and attach a screenshot of the error. If the problem is in the web or desktop version, if possible, take a screenshot from the developer console.

For Administrators: Unable to Add a Participant to a Chat, or the Chat Won't Open After Adding

Possible reasons:

• The account of the invited member is inactive on the server where it is registered. Check this yourself if the server is yours, or verify it through eXpress support;
• The corporate server of one of the participants is outdated or temporarily unavailable. Because of this, the chat is not synchronized between servers for all other participants. Keep your corporate server version up to date;

If everything is fine on your users' side and on your server, contact eXpress support: they will remove the participant from the chat or restore their access.

Messages Sent in a Bot-Created Chat Hang with an Error

Possible reason: DLPS key desynchronization between the server and client applications.

How to Resolve This?

Contact your organization’s support team or eXpress support.

For Administrators: Fixing DLPS Key Synchronization

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eCTS

Restarting the messaging container will reset the cache and update the keys. Follow these steps:

1. In the admin panel of the corporate server where the bot is located, collect the logs of the messaging container.
2. Reproduce the issue in the client application. If the keys_error error appears in the container logs, restart the messaging container using the command:
   cd /opt/express && dpl --dc restart messaging

Messages Show as Undelivered Although the iOS Recipient Receives Them

The sender sees messages as undelivered (with one checkmark), although the recipient on iOS has read them.

How to Resolve This?

To fix this, the recipient on iOS needs to:

1. Open Settings on iOS.
2. Go to Notifications.
3. Find the app and enable at least one of the notification display options: Lock Screen, Notification Center, Banners.

If notifications are disabled, messages appear as undelivered to the sender. On iOS, delivery confirmation is transmitted via push notifications, so it isn't sent without notification permission.

Incorrect Time in Messages

Messages have incorrect timestamps, e.g., replies are displayed before the original messages.

How to Resolve This?

Check time settings on the device.

Empty Chat List on iOS after Updating the App

If after updating the app on iOS the chat list is empty and loads slowly, the issue may be related to the app's data storage.

How to Resolve This?

Contact your organization's Support or eXpress Support: Support will help you recreate the application storage. You don't need to reinstall the app.

For Advanced Users: Collecting Logs for Diagnostics

In the mobile app on iOS, clear, and then collect general logs. In the logs, look for the error:
Type: REALM ERROR Message: can't instantiate migrated encrypted Realm, will create in-memory Realm instead Payload: exception: Migration is required due to the following errors:- Property 'Attachment.deepLinkData' has been added.- Property 'Chat.positionEventInsertedAt' has been added.- Property 'Message.buttonsAutoAdjust' has been added.- Property 'Message.sendStateRaw' has been added.- Property 'Message.needResend' has been removed.
The issue is related to the app's database (Realm). To recreate it without reinstalling, contact Support.

Error “Chat is not Available on Desktop. Open Chat on Mobile Device”

This error occurs if one of the chat participants has enabled privacy mode with the Mobile access only setting.

How to Resolve This?

To fix it, open the chat card, go to Confidential Mode, and disable Mobile access only.

“Threads Enabled Error” or “Threads Feature is not Supported”

Contact your organization's support team or the eXpress support.

For Administrators: Resolving Disabled Threads Issue

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eCTS

If a chat or channel has a participant with a backend version below 2.8, an error will appear when trying to enable threads.
Ensure that all participants have server software version 2.8 or higher. If outdated information about a participant with an old backend was cached in the chat, try updating the chat cache: add another user to the chat or assign any participant as an administrator.

Some Characters Disappear in Messages after Sending

Special characters such as `*_ are used for text formatting.

How to Resolve This?

To ensure text with such characters is delivered without distortion, format it as code (more details).