How to fix Team chat messages problem?

If you are experiencing issues with sending messages in Microsoft Teams chat, here are some potential solutions:

1. Check Recipient Status: Ensure that the recipient is not set to Offline or Do Not Disturb in Skype for Business, as this can prevent messages from being sent successfully.
2. Both Users Must Use Teams: Make sure that both the sender and recipient are using Microsoft Teams. If the recipient is using Skype for Business, this may lead to message delivery failures.
3. File Sharing Settings: If you are trying to share files and encountering issues, check the sharing settings. For group chats with more than 50 participants, ensure the file sharing setting is appropriate (e.g., set to People in your organization or Anyone if external participants are involved).
4. Run Diagnostics: If the issue persists, consider running diagnostics available in the Microsoft 365 Admin Center to identify any underlying problems affecting chat functionality.

If these steps do not resolve the issue, you may need to contact Microsoft support for further assistance.

References:

• Microsoft Teams user cannot send a message in Skype for Business
• Can't share files in a large group chat or meeting chat
• Error when uploading files to a Teams chat