On one of my sub accounts I cannot receive any POP3 emails and get the Outlook message:
" Receiving' reported error (0x8004210E) : 'Your mailbox is temporarily unavailable because another e-mail message is being delivered to it or another mail application is accessing it. The server responded: -ERR [IN-USE] maildrop busy."
There is no other device (of mine) accessing the account, sending mail is OK, and webmail works. It is not the settings as all my other subaccounts work and it is not a password issue as webmail works.
What is wrong?
A common problem, but it is not at my end, none of my devices can download messages from this account via POP3 since yesterday morning, so the issue is at the mail server.
Login to the sub account using webmail and see if there is anything unusual, like a large file waiting there.
I have just noticed that webmail is not receiving any new messages either, but it can send them.