Understanding POP errors with email
Errors are made. Errors also become apparent frequently with e-mail: instead of the e-mails you expected, you get an error message, a POP error message, if your account is set up to receive e-mails using the Post Office protocol.
POP status codes
Some things can go wrong in this process of receiving mail. The server from which you usually receive your email may not answer a call at all. Or maybe your password is wrong (but maybe the server password is wrong, due to some software problem). The server could also run into some internal problems and respond with an error code.
Fortunately, a POP server is very clear about its status. It knows basically two answers: the positive + OK and the negative -ERR. Of course, this is a bit vague if you want to know what has gone wrong.
As it turns out, +OK and -ERR are all the new code you need to learn if you want to understand POP error messages. Everything else is normal code: human language. Obviously, the Mail Protocol was designed by people for people. More detailed information about the -ERR server response is provided in plain English, following the -ERR message. While POP servers are not required to offer this additional information, most do.
POP error messages
The first thing that can go wrong (besides the server being completely down) is the POP server not recognizing your username. Maybe you typed wrong, maybe the database the server uses to identify users. Perhaps a flood has destroyed all the storage where mailboxes are kept at your ISP.
When a POP server does not recognize your username, it will usually respond with: -EKA mailbox unknown .
Right after the username comes the password and another chance for errors. Errors, this is correct, because in addition to the password that does not match the username ( -EKK invalid password ) the POP server can run into another problem. A POP mailbox can only be accessed by one incoming connection at a time. If your mail checker is already connected to your email account, your email program cannot access the same account at the same time. In such cases, when the mailbox is already locked by another process, the POP server returns: – ERR Unable to lock the mailbox .
Once you’ve successfully logged into the account, a POP client will typically start retrieving messages, one at a time. When it requests a message from the server, a negative response is possible: -ERR no such message exists. It looks like the client has a problem. The same response may be returned when the email client tries to mark a message for deletion that does not exist (or has already been marked for deletion).
When a POP session ends, all messages marked for deletion are usually permanently deleted from the server. If the POP server cannot remove all messages (probably due to lack of resources), it returns an error: -EC some deleted messages were not removed .
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Since the Post Office protocol is so simple, there are only a few things that can go wrong, and only a few error messages. All errors returned by a POP server are actually messages and not simple, cryptic codes.
If your email program converts these important error messages into non-descriptive error boxes, it’s probably best to try it yourself. Start a DOS prompt and telnet directly to your email account. Type telnet . Typically, the port used for POP is 110. A typical command might look like this, for example: telnet pop.myisp.com 110 .
When the server greets you with a happy + OK , follow the process outlined in The Post Office protocol and you should be able to identify the error. At least if everything works fine, you know the problem is really with your email client, not your email server.
