I have just started using [and donated to], Thunderbird on this newer PC. However, I cannot reply to emails, getting an error message stating that the sending failed because the SMTP server timed out. This happens even if I type just one letter as a reply and hit send. I have been using Thunderbird for a couple of years on my other recalcitrant PC, and have never had this problem. I have checked and all settings are exactly the same on both computers, same security programs, everything. Some internet articles say that it could be the security system, I disabled that, but the problem persists. What is going on? So naturally, if I need to reply to you, I will have to use the other computer, which randomly shuts down at inopportune times. Regards, Theo Beeltje.