The server sets the limits on the number of cached connections.

If you use a phone to also view emails on server then that will also count towards number of connections. So, first make sure your phone has properly disconnected from the server. If you have an apple device (eg: ipad) getting mail turn it off. They have no limit in the number connections they will use which makes sharing difficult.

I am receiving the ""Unable to connect to your IMAP server. You may have exceeded the maximum number of connections to this server. If so, use the Advanced IMAP Server Settings dialog to reduce the number of cached connections." error message.

I am running Thunderbird version 68.2.1 under windows 10. There are four accounts connected via Thunderbird. I also connect using a Samsung S9.

I have tried varying the number of permitted IMAP connections between 1 and 10 with no result. I have also disabled the Norton incoming email scan, again to no avail. The strange thing is that all of the accounts seem to be working perfectly.

Doesn't seen to make any sense.

Email servers place limits on the number of inbound connections to the server to prevent users from opening up too many concurrent sessions. Unfortunately, this restriction can impact legitimate users who have multiple computers connecting to their server from behind a firewall or a single computer that takes advantage of mailbox caching.

The error you are seeing indicates that the server has set a limit in the total amount of connections that you can make with your account (across all devices at that current time) and you have reached that limit.

It results in the exceeded max number of connections message that you are seeing.

Reducing the amount of folders that you are synchonising should resolve this issue. It can also help if you increase the checking for new mail interval to at least 10 minutes.

Set a lower threshold in Thunderbird for each mail account. Account Settings > Server Settings > 'Advanced' button Choose lower than 5 eg: 3 or even 1

Phones, ipad etc: eg: Make sure the Samsung has disconnected from server and is temporarilly switched off.

To force closure of connections to reset everything:

For one of your accounts:

• Right click on imap mail account in Folder Pane and select 'Settings'
• Select 'Server Settings'
• uncheck 'check for new messages at start up'
• uncheck 'check for new messages every xx minutes'
• uncheck 'allow immediate server notifications when new messages arrive'
• click on 'Advanced' button
• set the 'max number of server connections' to 3
• click on OK

• Click on OK

Restart Thunderbird. See what happens when you start Thunderbird. If no improvement restore all 3 of check for new messages etc, set 'check for new messages every 10 minutes' or more, but leave the mac connections set as 3. Then do the same process for another account. Repeat until checked all accounts.

I am having the same problem with Thunderbird "unable to connect to your Imap server...." What is considered as the amount of folders that are sychronized?give an example please. Also what is meant by : The error you are seeing indicates that the server has set a limit in the total amount of connections that you can make with your account (across all devices at that current time) and you have reached that limit.

It results in the exceeded max number of connections message that you are seeing.

Another possibility for causing exceeded max number of connections message that you are seeing. It is possible the Anti-Virus product on your computer is scanning incoming/outgoing emails and keeping a session open. Test by starting computer in 'Safe Mode with Networking' and then start Thunderbird or stop your AV product from scanning Thunderbird folders on start up and stop scanning incoming and outgoing emails.