Hi, Long time enjoyer of mozilla software here. Recently I've run into a very strange issue. It appears as if an email address in Thunderbird is blocked somehow. Whenever I try to send to, or send from this email address, it gives an error. See examples below. Please note, if I use a different account to send the email, there's no problems. If I use webmail to do the same thing, no problems If I use an app on my phone to do the same thing, no problems. So I am pretty sure the issue is in Thunderbird. Also note this is a 'catch all' account - so the account is configured to be able to send from any address within the same domain, through a single configured identity. Any other addresses work fine. There's just one specific address that gives the problem. I know I can easily save myself some headaches and change the email address, but I don't like having strange problems and want to figure out what is wrong. If anyone has any idea what could be going on or if you need more information, let me know. Example error when sending '''from '''the address: Sending of the message failed. An error occurred while sending mail. The mail server responded: Verification failed for <someaddress@domain.com> Sender verify failed. Please check the message recipient "someaddress@domain.com" and try again. Example error when sending '''to''' the address: Sending of the message failed. An error occurred while sending mail. The mail server responded: No such recipient here. Please check the message recipient "someaddress@domain.com" and try again