I have developed an application that authenticates with the podXXXXX.outlook.com / m.outlook.com POP3 service repeatedly every 5 minutes. The account used is created on Office 365 and is used for testing only. This works fine 80-85 percent of the time, but at least once every hour it fails. Once it fails it always tells me that username or password is incorrect (-ERR Logon failure: unknown user name or bad password).
I have debugged the issue and can see that the actually transmitted username and password are correct so the error seems to be related to the POP3 service internal handling of authentication.
I have to mention that my app being tested is running on a web server that is always on / has constant Internet access in a professional hosting service center. I have a hard time accepting that network failures could be the cause. In those cases I would
anyway expect a timeout or network error instead and not an authentication error.
I use POP3 only because the mailbox being tested it emptied after download of an email. I use no other functionality. Microsoft Partner Support recommended IMAP due to functionality, but the exact same authentication error pattern occur with that service.
Though this is not a critical issue, I still want to find out what is causing this.
I apologize if this is not the right forum, but was referred from Microsoft Partner Support (see the thread here
POP3 authentication recurring failures). They felt this was a development issue and maybe it is, but so far it does not appear to be.
Best Regards,
Ronnie Huang-Andreasen