Can't get into email - demands password



I can't access windows mail - system keeps asking for user name and password but then won't accept whatever I type in. This is error message:

Account: 'mail.btinternet.com', Server: 'mail.btinternet.com', Protocol: POP3, Server Response: '-ERR popgate argument(s) missing.', Port: 110, Secure(SSL): No, Server Error: 0x800CCC90, Error Number: 0x800CCC91

Think problem may have started with last Windows security update?

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