Mail Certificate /ACTUAL/ location?

i am back to getting multiple click throughs for "Continue" for unrecognized certificates for at least ten email addresses. gmail. icloud. domain based emails. all using IMAP (not that it matters).

at one point a apple tech showed me how i could APPROVE a certificate that was located in a folder (i guess it was the Mail folder). this was done by opening an independent file and checking approve and was DIFFERENT than clicking approval from the dialog thrown by Mail when this happens.

anyone done this or know where to find it or the file extension for these files?

it seemed to work after years of aggravation and now that aggravation is back...

thanks