Outlook 365 finds an imap folder among others that is locked.

Windows Microsoft outlook 365
2 users are accessing the same imap mail server with lots of folders.
One of the users has found a folder that they can’t add an email to as a sub folder under the inbox. The other user and myself have no problems adding or deleting emails from this folder

Why is one user unable to access the folder because of “permissions”?

Where do I find the permissions?

Thanks for your thoughts and help.

Peter