Are there any error messages when you add this guest to the channel?
Which channel did you want to add?
Please notice that shared channel cannot add guest accounts. Only the users who are owners or members of the shared channel can access the channel.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.