I can't see one of my mailboxes in Mail
I can't see one of my mailboxes in the left column in Apple's Mail program. I'm receiving emails to the mailbox but I don't see the Mail folder.
I have a MacBook Pro 16" and am using macOS Catalina Version 10.15.6.
Can anyone help me?
Thanks!
[Re-Titled by Moderator]
MacBook, OS X 10.11