I am unable to download any mail since yesterday. My Client(Thunderbird) reports that "POP3 low level authentication failed". Your mail server seems to reject my password, which I can still use to login via the web interface. I tried deleting the account and setting it it up from scratch, but to no avail. What gives ?

Could you please email us more detailed info? You have a free service account, you can use regular SMTP/POP3 only. For IMAP and SSL support, you need to upgrade to our paid service.

I just discovered that the culprit has apparently been the new version of Avast! antivirus and in particular its mail shield component. After disabling it I'm again able to download my mail. I'm reporting it for the benefit of your knowlege base, so please make note of it in case it happened to another user.