The server has limits on number of cached connections. Those connections are a total of connections you have made and that includes accessing via Thunderbird on one computer and via a phone or another computer. So basically, it is you who have to shut down cached connections.

Most problems occur if you connect to server via aphone and do not disconnect. So if you use a phone then switch it off so it disconnects your mail from server.

I've had people use a computer at work to see emails and then go home and try to connect on another computer and then get a problem because they never exited the email client to shut down cached connections being used. In Thunderbird you could try setting a much lower setting - In Account Settings Select 'Server Settings' click on 'Advanced' button

'Maximum number of cached connections' - by default it is 5. I suggest you start off by seeing if 3 is more suitable. Then click on OK

Now exit Thunderbird and wait a good 10 minutes for the server to completely switch off the cached connections.

Start Thunderbird.

Hello, I have been having this issue on and off for months now and no matter the number of connections I set it to it keeps happening. I only have a phone and a laptop that connects to my email account. When the problem happens on Thunderbird my iphone mail app also has issues retrieving messages.

I just tried shutting down my laptop and my phone for 2 hours then when logging back in the issue still persists on both. I can however connect to the service providers web mail app, which is very un-user friendly, which is why I use Thunderbird.

How long does it take for the connections to be cleared out? Is the due to the service provider limitations?

Also, one thing that doesn't make sense to me and hoping someone can explain, why would we want to decrease the number of connections if we have surpassed the maximum, wouldn't we want to increase it? In any case, I have tried lowering and increasing and nothing makes a difference.

Is there something else I can try? Any help would be greatly appreciated!!

re :why would we want to decrease the number of connections if we have surpassed the maximum, wouldn't we want to increase it?

The server sets the number of cached connections, so you cannot increase it.

Once you have set number of cached connection to eg: 1 and closed all connection - exited Thunderbird and switched off phone then it takes a short while before the server realises this.

The reason for limiting the number of connections in Thunderbird to eg: 1 then Thunderbird will limit number it uses. If you then started up Thunderbird again and not switched on phone then connections should be ok. But phones are notorious for not clearing cached connections because many people do not switch them off for good periods of time.

It's also worth checking if you have another email client on computer which may still be operating in the background. I have come across someone who previously used Outlook. Unknown to the user, Outlook was still receiving emails - all in the background and this was using up a load of cached connections. They then made sure Outlook did not have the email address set up by removing it and closed it again.

Also note the connections are specifically to that emails address, so then the question is - could someone else have access to the same account? I came across someone who shared their email address with a partner and they were accessing it on another computer. Could this apply to you?