Some things to check:

Firefox: - Have you installed any plugin that rewrites a request for HTTP to HTTPS. - Have you enabled the HTTPS-only mode in Firefox settings

Website server - Does the server have redirect rule set to redirect requests for port 80 to port 443. If you own this site, you could check you web server's config.

I have the default plugins

- OpenH264 Video Codec provided by Cisco Systems, Inc.
- Widevine Content Decryption Module provided by Google Inc.

HTTPS-Only mode is turned off.

Website Server

- There is not a website running on this server. Therefore I expect it to fail on port 80.

I even specified http://server.domain.com:80/

Stilled failed on https://server.domain.com/

No, never.

How are you forcing a specific port ? What protocol do you or does Firefox use ? If you use the https:// protocol or Firefox forces this protocol then Firefox may not want to use port 80.

in the address bar I use http://lillian.lafvb.com:80/ trying to force all of the right things but then Firefox fails on the address https://lillian.lafvb.com/ . This is an internal web site.

I think that Firefox doesn't want to use port 80. But there is no reason for us to use https on an internal web site.

- Robert