Is it your e-mail account password that does not work?

You must re-set it with your e-mail service provider.

It is my Thunderbird Firefox indentification code that no longer works.

What is a "Thunderbird Firefox indentification code" or "Thunderbird Firefox password"?

In Thunderbird, there is a "primary password" that controls access to e-mail account passwords. Is that what is not working?

Would you please post a screenshot showing the failure, perhaps in the form of an error message?

My e-mail service provider [Telia] did a check and claimed that there was no problem as I could access e-letters at its site.

I am unable to do a screen shot.

Here is exactly what is on a note in the middle of the page that appears after I am requested to enter my "password for [my e-mail address] on mailin.telia.com":

To the upper left is the circular Thunderbird/Firefox icon followed by the words "Log in to the account [my e-mail address] failed:" Under that line, to the left is a large circle with a question mark [?] in the middle followed by the words "Log in to servermail.telia.com with user name [my e-mail address] failed. Under that appears three boxes with the following words: Box 1: "Retry"; Box 2: "Enter new password"; Box 3: "Cancel."

A correction to my last post: servermail.telia.com is incorrect. It should read server mailin.telia.com

A correction to my last post: servermail.telia.com is incorrect. It should read server mailin.telia.com

That is about your password for Telia.

I found some indications on the Web that Telia needs Thunderbird to use an application password. Maybe that is what you have been referring to. The application password is specific to Thunderbird but it is controlled by Telia.

If you do not have one, you may need to get one from Telia. If you have one but have forgotten it, you will need to get a new one.

According to Telia, there was no problem with the code as it worked for me to get through to Telia when Telia made its test.. Could there be some problem with the "mailin" unit of the procedure?

According to Telia, there was no problem with the code as it worked for me to get through to Telia when Telia made its test.

You said that you accessed mail at their site. Accessing mail at their site is different from accessing it from Thunderbird. Do you have an application password from Telia for Thunderbird? Do you know whether or not you need one?

Could there be some problem with the "mailin" unit of the procedure?

Yes, and other information for the incoming and outgoing server could be wrong too. You'll want to confirm with Telia that all your settings are correct. Incoming server settings are in account settings > server settings. Outgoing server settings are in account settings > click on account name > edit outoing server.

Here's what telia.com says:

Inkommande server: mailin.telia.com IMAP-port: 993 med SSL POP3-port: 995 med SSL Utgående smtp-server: mailout.telia.com Smtp-port: 465 med SSL Smtp-autentisering: På Användarnamn: Hela din mailadress Lösenord: Samma lösenord som du hade tidigare

It is still not clear to me whether or not an application password is needed.

Thank you. i will contact them tomorrow and get back to you.