Thunderbird Keeps Asking to Add The Same SSL Security Exception Again and Again!
SSL, short for Secure Sockets Layer, is a standard security system established to secure a connection over any kind of network. It is now widespread across many programs, platforms, and operating systems. It is usually described as a security protocol between client and server, client being you and server being from where you are requesting data.
SSL Error In Thunderbird
In the case of Mozilla Thunderbird, client is Thunderbird itself (You) which is requesting your mail servers for data (emails, contacts, etc.). Thunderbird checks for SSL (and other security concerns) certificates associated with the servers. If the check isn’t passed, Thunderbird warns about the risk of making the connection regardless of the lack of SSL.
If you do proceed anyway, Thunderbird adds that to the exceptions list and that list is stored as a cert8.db file. This is called certificate store file.
The simply solution for the problem of Thunderbird constantly asking for the same exception to add to the list again and again is to delete the file and let Thunderbird re-build it itself. This is because in most cases cert8.db file is corrupt and requires rebuilding.
Deleting this file will remove all other exceptions that you might have added, so you might have to add them again. But at least you get a fresh install of all security certificates.
This file is located inside Thunderbird Profile folder. You can locate it here: ~/Library/Thunderbird/Profiles//, unless you manually move the default location of the profile folder. Close Thunderbird, look for cert8.db file within the profile folder, and delete it.
Launch Thunderbird again. It will automatically rebuild this file from scratch.
Now, whenever you want to connect to a server that is not protected by SSL certificate but you sure it’s safe, you can add that to the exception.
A cautionary note: Proceed to any unsafe connection very carefully. Even if You are sure, it is not a bad habit to double check everything. A general thumb of rule is to not connect to an unsafe server unless you absolutely have to.