What about your Authorities tab. Do you still have the "Built-in Object Token" listings there?

Could you review these articles:

• What do the security warning codes mean?
• How to troubleshoot security error codes on secure websites

Does that help identify a culprit?

Yes, in Authorities tab certs are an available with "Built-in Object Token".

if i add exception in Advanced menu - this solve for added site. but not all sites have this option. for example, i cant add github.com

and before deletion all sites do not need to add exception.

I do NOT recommend adding exceptions. We need to figure out the reason for the problem. It could be security software, it could be malware. Did you review the two articles?

yes, i read, but didn't solve.

this happened when i removed the certs from the server tab. only this action affected the error.

what information i should be give?

Are you getting the error code SEC_ERROR_UNKNOWN_ISSUER ?

If so, click that, and Firefox should display a coded version of the certificate that does not meet its standards. There should be a button to copy that so you can paste it into a reply. A volunteer will decode it and see whether it points to a specific intermediary. Or you can give that a try yourself. I use https://certlogik.com/decoder/ but of course there must be many others as well.

help info

help info

As far as I can tell, that is the real certificate. I wonder if your cert8.db file has become corrupted. Could you try the steps under "Corrupted certificate store" in this article if you haven't already: What do the security warning codes mean?

great! big thanks.