Thunderbird Community Forum

Hello. E-mail stopped working this morning. I did not change anything! I have used Thandep very many years, no prolems at all. But now it cannot receive on send e-mails. Pls let me know the situation!

no response to mail.inet.fi while using account matti.viitanen@pp.inet.fi

I am using Thunderbird 149.0 (64‑bit) on Windows 11 25H2.

Recently, Thunderbird has started showing error messages for my Outlook.com accounts every time the program starts. Sign‑in fails, and sometimes an additional error appears: Error code 12.

I have three Outlook.com accounts in Thunderbird. All of them use the IMAP server: outlook.office365.com.

When I open and close Thunderbird several times, the login eventually succeeds at random. After that, Thunderbird re-downloads all emails from the server, which suggests that the OAuth2 token is not updating correctly. All accounts are using OAuth2 authentication. One suggestion was to switch to the App Password method, because Outlook.com OAuth2 is said to be unstable in third‑party applications. Question: Is the App Password method less secure than OAuth2, and is it advisable to switch to it for Outlook.com accounts in Thunderbird or something else what i can do?

Hi.

I have several calendars added to Thunderbird, but yesterday(3/5/2026) I noticed that all the calendars are not showing the events even though they are visible. Have you any clue whats this is all about?

Saisin Avattua ja Lähetettyä viestini uudessa sähköpostini :marketta.jokinen@outlook.com minulle HP-koneelle asetettiin Tänään Reititki 4G-( operaattorini tela lopetti3G)

Minun SÄHKÖPOSTINI: marketta.jokinen@outlook.com En saa LÄHETETTYÄ sähköpostiani/mutta-saapuvat toimii. Voisitteko AUTTAA-että voisin LÄHETTÄÄ viestejäni. Terv.Marketta Jokinen Alinenkatu37.37100Nokia +358400633137