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Just recently Thunderbird messages sent are not being received

Joe Jefferies
Joe Jefferies
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We have a small office network (7 users) using Thunderbird (IMAP) and Gmail. It has worked virtually trouble free for several years but suddenly several users are finding that sent emails never arrive. These emails do go into sent box and sometimes there is a :-

'Cannot connect to IMAP server' message

GMail Webmail appears to wok perfectly on these accounts (though it doesn't get a great deal of use so I can.t be sure it is 100%)

I have tried deleting user password and the re-entering when prompted and also deleting an account and re-installing it. OS Win7 Thunderbird 52.8.0

Incoming Server imap.gmail.com Port 993 Security SSL Authentification OAuth2

Outgoing server smtp.gmail.com Port 465 Security SSL Authentification OAuth2

Extensions:- Lightning 5.4.8 Bullguard 18.0 (Outgoing email scan OFF)


I would be very grateful for any help on this problem

We have a small office network (7 users) using Thunderbird (IMAP) and Gmail. It has worked virtually trouble free for several years but suddenly several users are finding that sent emails never arrive. These emails do go into sent box and sometimes there is a :- 'Cannot connect to IMAP server' message GMail Webmail appears to wok perfectly on these accounts (though it doesn't get a great deal of use so I can.t be sure it is 100%) I have tried deleting user password and the re-entering when prompted and also deleting an account and re-installing it. OS Win7 Thunderbird 52.8.0 Incoming Server imap.gmail.com Port 993 Security SSL Authentification OAuth2 Outgoing server smtp.gmail.com Port 465 Security SSL Authentification OAuth2 Extensions:- Lightning 5.4.8 Bullguard 18.0 (Outgoing email scan OFF) I would be very grateful for any help on this problem

All Replies (2)

Wayne Mery
Wayne Mery
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  • Top 10 Contributor
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Perhaps the problem is https://www.lifewire.com/what-is-the-simultaneous-gmail-imap-connection-limit-4023699 ?

Joe Jefferies
Joe Jefferies Question owner
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Wayne Thank you for your suggestion. I had considered this but I have tried shutting down all but one machine. I also use GMvault (for backup) but I ensured that this was disabled for my test. Sorry I should have mentioned this in my notes

Joe