Explanation
Table Description automatically generated

Explanation
To troubleshoot the reported issues, you should check the following configuration locations:
For issue 1, you should check the channel setting. You can edit the channel setting by clicking on
the three dots next to the channel name and selecting Manage channel. There, you can see if the channel
is moderated or not. If it is moderated, only the channel moderators and owners can start new posts in
the channel1.
For issue 2, you should check the team setting. You can edit the team setting by clicking on the three
dots next to the team name and selecting Manage team. There, you can see if the team members have
permission to create and update channels or not2. You can also see if the team has reached the
maximum number of channels allowed, which is 2003.
For issue 3, you should check the teams policies. You can view and edit the teams policies in
the Microsoft Teams admin center. There, you can see if the users have permission to delete channels or
not. You can also see if the channel is a private channel, which can only be deleted by its owner.

Explanation
Graphical user interface, text, application Description automatically generated

Reference:
https://docs.microsoft.com/en-us/azure/active-directory/enterprise-users/groups-lifecycle