HAproxy and Thunderbird Issue
Hi all, I spent my last working week to resolve an issue with HAproxy and Thunderbird IMAP clients.
Due to SSL/TLS restrictions (min version TLS 1.2), I set a HAproxy in front of my IMAP Server and I configured it as SSL/TLS passthrough (TCP Layer, not HTTP Layer).
It's work but always, using Thunderbird (from v.68.x to recent one) and surfing between my email directories, I receive this message: "Unable to connect to your IMAP server. You may have exceeded the maximum number of connections to this server."
If I don't use HAproxy and read (with security exceptions) emails directly to my own IMAP server, I never have the message above.
If I set "Maximum number of server connection to cache" parameter to 1 in IMAP settings, I never have the message above but Thunderbird become too much slow. I don't want to modify this default parameter and I would like to understand what happens in this situation.
I tried to modify multiple configuration parameters on HAproxy backend config but I had always same issue.
May you help me?
Thanks in advance.
alfionas மூலமாக திருத்தப்பட்டது
All Replies (4)
That message is from the server. If you use a phone or other device/laptop etc to connect to server to see emails then it is likely there is still some connections that have not closed.
You need to exit/close all connections to the server in all devices including Thunderbird. So switch off everything. Wait for a while as server needs time to close them. Have a cup of tea :)
start Thunderbird.
Toad-Hall said
That message is from the server. If you use a phone or other device/laptop etc to connect to server to see emails then it is likely there is still some connections that have not closed. You need to exit/close all connections to the server in all devices including Thunderbird. So switch off everything. Wait for a while as server needs time to close them. Have a cup of tea :) start Thunderbird.
Hi Toad-Hall, thanks for your reply. I think it's a problem inside Thunderbird and I would like to understand why. If I use proprietary client (that dont't use IMAP protocol) or Windows Mail (IMAP) the system works normally.
Because I have a lot of desktop Thunderbird clients I have to resolve this issue.
You have been told by the server that you have opened too many concurrent sessions. The server sets this limit not Thunderbird, but Thunderbird can try to remedy that by you lowering the cache to 1. However, if you have other programs, devices, etc accessing the same server and they are hogging the number of allowed sessions then the server will block Thunderbird's attempts.
That 'lowering the cache to 1' does not come info effect until you exit Thunderbird and also exit from ALL other clients, webmail, phone, other computer etc that are accessing that server. It's not just Thunderbird that is accessing that server.
There is a period of time - not very long, when the server needs to close down opened sessions. It is not a problem in Thunderbird if you have set cache limit to 1. Thunderbird does not control the number of concurrent sessions the server allows nor does it control you opening too many concurrent sessions on other devices. But it can control the number of sessions within Thunderbird once all is reset and all Thunderbird mail accounts accessing server are set to have cache of 1. Because you have too many opened sessions not just in Thunderbird - in everything that is connecting to server, therefore the server will not allow Thunderbird access.
You have to close all concurrent sessions to get back the status quo by exiting all connections to server.
I've had people stuck with same issue and it was all because they used an apple phone connecting to receive emails and it was not closing the sessions.
Toad-Hall மூலமாக திருத்தப்பட்டது
Toad-Hall said
You have been told by the server that you have opened too many concurrent sessions. The server sets this limit not Thunderbird, but Thunderbird can try to remedy that by you lowering the cache to 1. However, if you have other programs, devices, etc accessing the same server and they are hogging the number of allowed sessions then the server will block Thunderbird's attempts. That 'lowering the cache to 1' does not come info effect until you exit Thunderbird and also exit from ALL other clients, webmail, phone, other computer etc that are accessing that server. It's not just Thunderbird that is accessing that server. There is a period of time - not very long, when the server needs to close down opened sessions. It is not a problem in Thunderbird if you have set cache limit to 1. Thunderbird does not control the number of concurrent sessions the server allows nor does it control you opening too many concurrent sessions on other devices. But it can control the number of sessions within Thunderbird once all is reset and all Thunderbird mail accounts accessing server are set to have cache of 1. Because you have too many opened sessions not just in Thunderbird - in everything that is connecting to server, therefore the server will not allow Thunderbird access. You have to close all concurrent sessions to get back the status quo by exiting all connections to server. I've had people stuck with same issue and it was all because they used an apple phone connecting to receive emails and it was not closing the sessions.
Toad-Hall, I understood everything you said. I'm agree with you but the issue isn't server resources. My tests were made using only one Thunderbird client connected to my IMAP server. There weren't other concurrents connection. It's something inside interactions by Thunderbird clients to server IMAP through HAproxy.