Resolve Firefox SSL connection errors

A quick blog post because I ran into the issue of Firefox not connecting to certain HTTPS sites, and I could not find a solution. Well, the only offered solution was “clear your profile” but I don’t want to do that. It takes a lot of effort to get back up running, even with Firefox sync.

The symptoms

I was for a longer time not able to visit the website from the tax authority of my country (Belastingdienst), but suddenly I could not visit Twitter as well.

• For the HTTPS connection to Belastingdienst I ran into PR_CONNECT_RESET_ERROR
• For the HTTPS connection to Twitter I had simply “connection failed” without any details

Check your SSL/TLS settings

First of all, start a Firefox instance with a clean profile. In your current instance and clean instance, compare the results of the about:config pages. Search on “https”, “ssl”, and “tls”. Check if you have any keys that deviate from the defaults, shown in bold, and reset them.

Clear your local caches

Go to %localappdata%\mozilla\firefox. You can find a folder there called “Profiles”. You can delete this. It only contains cached data.

After deleting everything should be working again.

Happy browsing!