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Tracing interactions between Thunderbird and the incoming POP3 mail server

  • 5 replies
  • 1 has this problem
  • 2 views
  • Last reply by SandyDog

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I am experiencing a problem using Thunderbird 91.10.0 when attempting to log-in to my ISP's POP3 mail server. The problem does not occur all of the time, however, once it occurs it persists for days.

The ISP's POP3 mail server uses SSL/TLS with Normal Password Authentication on port 995. I never permit Thunderbird to "rememeber " the password for this account.

The issue is that after entering a valid password in the "Enter your Password" pop-up dialog box and subsequently receiving no error messages, no e-mails are fetched. When using a web browser interface to the same POP3 server it can be seen that quite a few e-mails are present.

As an interesting tidibt, it was discovered that entering an incorrect/invalid password in the "Enter your Password" pop-up dilog box produces the same incorrect result. For this interaction I would have expected the "Sending of username did not succeed. Mail server responded: authentication failed: LOGIN failed" pop-up. However, this does not occur.

So, my ISP and I would like to know if there is some facility within Thunderbird to trace the request and response interactions between Thunderbird and the POP3 server. If so, how do I enable it and see the corresponding information? At this point we (me and the ISP) do not understand what's going on leading to the incorrect and unexpected behavior.

As another tidbit of information, things work correctly when running Thunderbird 60.5.1 interacting with the same ISP. Even a very old version (45.7.0) of Thunderbird works fine with the same ISP (all connections settings are the same).

This is all very strange!

I am experiencing a problem using Thunderbird 91.10.0 when attempting to log-in to my ISP's POP3 mail server. The problem does not occur all of the time, however, once it occurs it persists for days. The ISP's POP3 mail server uses SSL/TLS with Normal Password Authentication on port 995. I never permit Thunderbird to "rememeber " the password for this account. The issue is that after entering a valid password in the "Enter your Password" pop-up dialog box and subsequently receiving no error messages, no e-mails are fetched. When using a web browser interface to the same POP3 server it can be seen that quite a few e-mails are present. As an interesting tidibt, it was discovered that entering an incorrect/invalid password in the "Enter your Password" pop-up dilog box produces the same incorrect result. For this interaction I would have expected the "Sending of username did not succeed. Mail server responded: authentication failed: LOGIN failed" pop-up. However, this does not occur. So, my ISP and I would like to know if there is some facility within Thunderbird to trace the request and response interactions between Thunderbird and the POP3 server. If so, how do I enable it and see the corresponding information? At this point we (me and the ISP) do not understand what's going on leading to the incorrect and unexpected behavior. As another tidbit of information, things work correctly when running Thunderbird 60.5.1 interacting with the same ISP. Even a very old version (45.7.0) of Thunderbird works fine with the same ISP (all connections settings are the same). This is all very strange!

All Replies (5)

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see https://wiki.mozilla.org/MailNews:Logging

Just be aware if you have an antivirus product it will be pretending to be the mail server in most circumstances and is a common point of failure. Windows safe mode with networking will generally remove that impediment for testing.

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Thank you Matt for the help and the pointer to the support article. I will see what I can discover!

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See if you have a 'log jam', where the oldest not downloaded mail is in effect causing a blockage or whether it could be something moved to server Spam.

  • Logon to webmail account using a browser.
  • Locate the oldest email which has not downloaded then either read it and delete it OR read it and move it out of the 'Inbox' into another folder.
  • Empty the Spam
  • Empty the Trash

In Thunderbird - Assuming you have already entered correct password Click on 'Get Messages' Report back on results.

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Hi folks. Thanks for the helpful replies. I am away on a bicycling trip, returning in a week. I'll be able to get back to working on this then. Sorry for the delay

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The issue seems to have nothing to do with the "log jam" as you described it. Rather it appears that for some unknown (so far) reason, the mail server-to-client connection gets dropped. Once that happens the ISP has to do some sort of a "reset" (this is done manually by the ISP staff) on their server and then things work well for some seemingly random period of time. Analysis is still ongoing.