Need an SSL Certificate Guru - Unix, AWS Lightsail, Nginx

I have an AWS Lightsail instance that I set up a few years ago. I managed to muddle through getting the certificate setup for the server. I added an additional certificate for the Domain, and have kept that current. However, the original certificate has long since expired. The web site is using the domain certificate, but the service on port 5001 appears to be using the old certificate. I can get on the website and it's secure. I can hit the service via SSL with postman and postman doesn't complain. But when I try to hit the service via javascript in Chrome browser, I get: NET::ERR_CERT_DATE_INVALID. This server could not prove that it is csharpbaas.cloud; it's security certificate expired 542 days ago.