421 #4.4.5 Too many connections from your host

Question: I get this error from my SMTP server: 421 #4.4.5 Too many connections from your host What does it mean? Answer: The “too many connections from your host” error is the text of the error message that is coming back from the SMTP server. It indicates that the SMTP server has a limit on how many simultaneous open connections […]

-ERR Mailbox Locked

If you see this error when trying to login to a POP3 server, it most likely means that the server is only allowing a single connection (i.e. session) at a time for each mailbox, and than another user already has mailbox open.  It could also mean that the POP3 administrator temporarily locked the mailbox to prevent access.