This solution worked only temporary.
I was experiencing the same issue and re-installed the certificate. Worked in Firefox for about 2-3 days and the error has returned.
Funny thing is that my website works in IE, Chrome as well as Firefox for Android.
Anyone else able to assist? This is becoming a disruption for my business.
Welcome to the Community!
As the previous posting was on a much older thread, we have moved your inquiry in order to seek your specific remedy.
For our Community participants to better assist you...
What type of SSL are you using?
On what type of hosting plan is it installed?
What is the error that you're seeing on the certificate?