using firefox 76.0.1 64 bits, (on tc11.1_x64), trying to go at [Link deleted, Wiki is fixed. Rich]
I am on TC64 11.1 using FF v 77.0.1 and cert is valid.
If interested you should have an entry for
Sectigo ECC Domain Validation Secure Server CA
under
The USERTRUST Network
and to find that....go to Preferences -> Privacy and Security -> Certificates
tick the box for OCSP....
click the box to the right called View Certificates
Go to TAB=Authorities
(these are your root CA)
scroll to the bottom and go up 10 root CA to The usertrust etc
expand that root cert group and you should find
Sectigo ECC Domain Validation Secure Server CA
bottom line....keep your FF up to date please
Good luck
If interested a bit of the screenshot of cert
https://imgur.com/pqcDgaN