Additional team and channel-related features and issues within Microsoft Teams for business
Dear Cam Mou,
Good day!
Thank you for posting to Microsoft Community. We are glad to assist.
Based on the information you provided, it seems that the issue you are experiencing is due to the fact that you are attempting to share a channel between a Commercial cloud and a GCC cloud, which is not currently supported.
The verbiage "Shared channels between Commercial and GCC clouds are not supported" means that Commercial cannot interact with GCC or GCC High (cannot interact with GCC, and cannot interact with GCC high). I apologize for any confusion this may have caused. If you have any further questions or concerns, please let me know.
Appreciate your patience and understanding and thank you for your time and cooperation.
Sincerely,
Sherry | Microsoft Community Moderator