Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

This is what I get when I click on my bank icon:

Secure Connection Failed

An error occurred during a connection to radiusbank.com. Peer’s Certificate has been revoked.

Error code: SEC_ERROR_REVOKED_CERTIFICATE

   The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
   Please contact the website owners to inform them of this problem.

Learn more…

Secure Connection Failed

An error occurred during a connection to radiusbank.com. Peer’s Certificate has been revoked.

Error code: SEC_ERROR_REVOKED_CERTIFICATE

   The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
   Please contact the website owners to inform them of this problem.

Learn more…

When I visit the site, it sends me a brand new certificate issued yesterday.

Could you try clearing Firefox's Cache to see whether that lets your Firefox get the new certificate? See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes.

Any difference?

Thank you all for your help. I live abroad, 7 hours ahead, so didn't go through the process last night. This morning, I tried connecting again, before clearing the cache and miraculously, it went through without a hitch. Woo hoo, I'm literally back in business.

Again, thank you all and have a good week. Stay safe and healthy.