Firefox continually tells me "Secure Connection Failed"

This is the error message:

Secure Connection Failed
An error occurred during a connection to Ancestry(R) | Genealogy, Family Trees & Family History Records. PR_END_OF_FILE_ERROR
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.

If I actually paid attention to the message, I'd be informing half the websites I go to. Sometimes the page will reload after a couple of pages, other times not. I've done web searches and found solutions from 2018, none of which work. They always end up saying "if this doesn't work, contact your network administration". Not helpful.

I've tried turning off my VPN, turning off Bitdefender, basically turning off everything that protects the computer from attack, but to no avail. Does anyone have any helpful suggestions?

Firefox Version 96.0.1 64-bit
Windows 10 Version 2004, Build 19041.1415

@rosawoodsii

While I wouldn't touch Ancestry.com with a ten foot pole... I would imagine that it's one or more of the modules in Bitdefender, that's causing the problem.

I live by myself and am the only one that accesses this computer, but I run Bitdefender Internet Security (paid) with the following modules turned OFF...

Online Threat Prevention (ONLY have Web and Network protection turned ON)
Vulnerability, Ransomware Remediation and Antispam turned OFF
Privacy section... everything turned OFF.

I ONLY use the Antivirus, the Firewall and Advanced Threat Defense.

I've never had any issues with Bitdefender set like this. I've been using Bitdefender for 8 years now.
I also use backup software religiously. Namely, Macrium Reflect (free or paid).



P.S. I clicked your ancestry.com link, and I have no trouble going to that site with Firefox 96.0.1
Yes... this is the latest Firefox. I just have it tweaked a little.

Firefox... taming the beast part 2 !!