When you face this error, you should consider the following cases.
The user’s status is not shown as joined the group channel. When creating a group channel, don’t use the
invitation_status parameter, if you want to make a user join automatically. The default value is already set as
joined. You can check what the user’s current state is by calling this API.
If this issue occurs, update the invitation status of the users with the Accept an invitation API. The invited users status will change from invited to joined. Once joined, users can now chat in the group channel.
The maximum number of group channels that a user can join is 2,000. If a user who has already reached this limit receives an invitation to join a new channel, the invitation will be canceled automatically.
You can check the number of channels that the user has joined by calling this API.
If a user reaches the maximum number of channels they can join,the user should leave or delete a channel.