iMac Certificate chain broken

I write database software on the Mac since 1987. I have a 2015 27" iMac 5K. I have been running from an 8Tb external drive as the internal drive has failed (again). I need to keep this machine at OS 10.14.6 as I have to maintain older versions that can not run on the newer machines.

Once every couple of months, it will freeze, and when I restart, the printers are gone. Usually, running Disk First aid a couple of times fixes it. This time, no. So I found a 2Tb SSD. Did a Carbon Copy Clone of a base 10.14.6 system to the SSD. Cleared enough extraneous stuff from the 8Th and did a migration to the SSD.

Images in incoming email don't show, so I've moved email to my M1 Mini. Now I find that iTunes, which worked fine from the 8Tb drive will not share with my Apple TV. Invalid certificate chain. And Safari will not connect to a Zoom call citing a broken certificate chain.

I have lots of audio books, and Apple Books on newer operating systems (they used to be in iTunes) places them on the internal drive (unlike movies, where you can have multiple locations). On the initial migration to the M1 Mini, I almost filled it up with the books. I had to remove them - 496Gb of them - so there would be room on the 1Tb Mini.

So, I need to fix the certificates.