Maildrop opened for exclusive access by another user.

Question:
On our test server we get the following error. The mail server from which it is trying to download mails is Lotus Notes R8.

  FetchEmail:
    pop3-connect:
      Attempting to connect and log into POP3 server
      hostname: 10.176.4.16
      port: 110
      username: ***@***.com
      -ERR The system was unable to log ***@***.com in.  Maildrop 
opened for exclusive access by another user.

      Failed to login to POP3 server: login name and/or password is invalid
    uidl: 82D4C30C3587541665257211004899DC
    Failed to fetch email from mail server

Answer:
Apparently, your POP3 server does not allow simultaneous logins to the same email account. Unless you can prevent it, your program should wait a short time and re-try.

There is no source code associated with this article.