Make sure you are not blocking content.

https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop also see https://blog.mozilla.org/security/2021/03/23/introducing-smartblock/

https://support.mozilla.org/en-US/kb/smartblock-enhanced-tracking-protection

Diagnose Firefox issues using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

"Is the problem still there?"

No Sir. Thank you for your quick reply. www.spectrum.net loads perfectly in troubleshooting mode. Leads me to suspect an add-on/extension(?). When I isolate the cause, I will be back to mark as solved .. thanks to you.

edit: uBlock Origin. Weird though. I turned it off (exceptioned) for spectrum.net ... refreshed, no joy. Went to private mode .... no joy. Restarted machine, disabled Ublock, obtained joy @spectrum.net. Re-enabled Ublock, went to spectrum.net, told Ublock to exception spectrum.net, refreshed and boom. Problem gone. Just needed some coaxing it seems.

Thank you again for your superb support.

uBlock Origin. Your input was VERY helpful. Thank you.

Glad to help. Safe Surfing.