It worked fine yesterday 10/12 but not this day 11/12. I have not changed any setings with firebird. 2 of my 4 accounts still work fine. The two accounts that do not work is at the same ISP. I can send and receive mails properly when i log in att my ISP, but not when i use thunderbird. I just get this error message in swedish: "Det gick inte att skicka meddelandet. Meddelandet kunde av okänd anledning inte skickas med SMTP-servern hosting.performia.com. Kontrollera att dina inställningar för SMTP-server är riktiga och försök igen, eller kontakta din nätverksadministratör" In English: "Failed to send your message. The message could for unknown reasons not sent by the SMTP server hosting.performia.com. Check your settings for the SMTP server is correct and try again or contact your network administrator" I have not changed the setings and they look ok.