Why don't my message folders show in Thunderbird? (POP server)
I have two accounts in Thunderbird. The account that uses an IMAP server shows all of the message folders created and existing on the server. The account that uses a POP server only shows Inbox, Drafts, Sent, Junk and Trash, and except for Inbox where all the messages received reside, these folders appear to be local to this computer. The roughly twenty message folders that exist on the server and can be seen and accessed using Outlook or the mail utility on my iPhone don't show up at all.
Wšykne wótegrona (1)
Perhaps you should read this article on IMAP and POP https://support.mozilla.org/en-US/kb/glossary-terms-including-types-accounts?redirectlocale=en-US&redirectslug=Types-of-Accounts#w_mail-accounts.