Diag: Teams Federation

Hi @IBN

Thank you for posting your question in the Microsoft Q&A forum.   

Regarding your issue, may I kindly ask if you can answer a few questions so I can understand your issue better. 

• Are you trying to send an attach file to external users? Or are you trying to send chat, call, share screen etc on Teams?  
• Does this issue also happen with other users as well? 
• Do you have at least Teams admin rights?  
• Can you provide a screenshot (make sure you hide all of your personal information) if possible? 

If you wanted to send chat, call, share screen on Teams with external person with company domain have you asked your IT Admin to check if they have external access enabled yet. 

Here are a few steps you can try: 

Check External Access settings 

• Go to the Teams Admin Center: 
• Navigate to Users > External Access 
• Ensure the setting “Allow users to communicate with external Teams users” is enabled.
• 
• Add the external domain to the allowed list if needed 
• Confirm that the affected users have policies that allow external communication. 
• Both organization settings and user policies must be enabled 

For more details, please refer to: IT Admins - Manage external meetings and chat with people and organizations using Microsoft identities 

If you wanted to send attach files to external users on your company domain, you will have to add them as a guest to the channel because it is a known limitation of Microsoft and you cannot share files with external users. 

For more details, please refer to: Use guest access and external access to collaborate with people outside your organization 

Hope to hear back from you soon! 

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