We have recently moved to a new mail server. We currently have about 20 Thunderbird email clients on Windows in an office location and a macOS home machine. On all machin… (আরও পড়ুন)
We have recently moved to a new mail server. We currently have about 20 Thunderbird email clients on Windows in an office location and a macOS home machine. On all machines email is configured to use IMAP on hostname.com port 993 SSL/TLS with Normal Password and SMTP on hostname.com port 465 SSL/TLS with Normal Password.
The home machine is working 100% with no issues, it does have a much faster and lower latency internet connection than the office machines.
Many of the office machines are experiencing intermitent SMTP error messages when sending, intermitent, "unable to save mail in the Sent folder of the Inbox", messages and intermitent unable to move messages between folders.
I have checked and double checked the settings on affected machines - however, I believe a settings issue would result in nothing working, not intermitent functionality. Plus all is working fine on the home machine with the same settings (different OS, but ports and security settings all dictated by server).
With one client behaving properly, the server likwise behaving properly when addressed by the working client and the intermitent nature of the problems we are finding, I suspect we have some sort of network issue. Somthing timing out or a firewall/AV software causing a delay.
I have increased mailnews.tcptimeout on affected machines to 250 based on a forum article but this has had no effect (No idea of units here but if it is seconde then I am not supprised - the SMTP errors, when they happen are almost instantanious).
Any ideas on how to trobleshoot this problem further - The problem seems to get worse through the day, although that may just be peoples tollerance of an intermitent issue going down.
