POP3 0x426 authentication error

Setting up a POP3 access on Exchange SBS 2003 server (exchange Service pack 1) for mobile phone access. Original phone worked fine and started downloading mail, but second phone would not authenticate - then first phone also failed to authenticate. Tested from an internal Outlook POP3 account with same problem. Checked all user names and passwords.
Set POP3 logging to Max and found the error
Authentication attempt from (IP address) to (user e-mail address) has failed with error 0x426
Have restarted all services and rebooted server but cannot solve this problem.
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Any reason you are still on Exchange 2003 SP1? You should really update the machine to SP2 and the post service pack updates from Microsoft Update.

What format are you using for the username and password for POP3?

DaveBorgAuthor Commented:
Have not got around to updating to SP2. This is an occasional client for me.
We have used both username and domain\username
The service pack is over three years old. I don't consider service packs optional, you really should be looking to keep the servers up to date.

Both of the authentication methods you have used are wrong. For POP3 it is domain\username\alias format.

DaveBorgAuthor Commented:
Thanks Simon
I agree service packs should be applied but clients don't always want to pay to get it done.
In the past I have found username and password works fine but will take note of your suggestion for domain\username\alias which I have never used.
The problem seems to have corrected itself overnight - I must admit I am relieved but baffled.
Thanks for taking an interest and for your suggestion. As you are the only person to respoond and have added to my knowledge base I would like to offer you half points.

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