Firefox browser from Mozilla is making sure that your surfing activities online are secured as possible. If there are issues when suspicious connections occur or when there is no valid certificate, Firefox will not push through your connection to the website.
Seeing the error code SSL_ERROR_BAD_CERT_DOMAIN on Firefox web browser simply means that the website you are currently trying to access is using the wrong SSL certificate. The certificate is not valid for the said website hence it can be risky on your part, especially if you share your information.

In most instances, users will receive this error message: Your connection is not secure. The owner of “” has misconfigured their website improperly. To protect your information from being stolen, Firefox has not connected to this website. The certificate is only valid for the following names: SSL_ERROR_BAD_CERT_DOMAIN.
Possible Fixes for Firefox Browser SSL_ERROR_BAD_CERT_DOMAIN Error
Note that there can be varying reasons why the error message appears on your browser. It can be an outdated cache or a mismatched domain name. In some cases, the web address is wrong or if the SSL certificate is incorrectly installed.
#1 – Clear your Firefox Browser Cache
Go to the top of your browser screen and click Firefox. Select Preferences or Settings. Head over to the Privacy & Security option. Look for the Cookies and Site Data option. Click the Clear Data button. Beside the option When, select Everything. Now, tick the box next to Temporary cached files and pages. Click the Clear button.
#2 – Verify SSL Certificate Validity
On the error message, look for the option Add Exception and click it. Select Get Certificate. Click the View button to show more details. You will then see the expiry date of the SSL Certificate.
In Closing
Encountering errors can leave us frustrated but it does not have to stay for so long. You can try to fix the problems on your Firefox browser with the solutions above.