A colleague reached out to me to help with a customer's Logic App issue. They were trying to make what looked like a simple HTTP request to a Jira API but were getting back an SSL error. The root of the error was that the customer was securing the API endpoint with a certificate generated from a private Certificate Authority in their environment. Because this certificate was not signed by VeriSign, GoDaddy or other public certificate authority, and the Logic App HTTP Connector was failing as it did not trust the issuer.
The fix for this is simple as it turns out but required a bit of reading the manual. First, go to Certificates and load the root CA and any intermediate CAs you might be using to the store.
Then, to get the Logic App to load these certs, go to Environment Variables and add a new setting WEBSITE_LOAD_ROOT_CERTIFICATES and place the thumbprints of the added root and intermediate CAs as a comma delimited string (hat tip to Glen from our consulting team for figuring that one out). When you save the change, the service will restart and will now trust these private certificates.
It should be noted that Logic Apps Standard is a flavor of Azure App Service, so this fix would also work for a regular App Service or a Function App as well.
I hope this helps you out!
Microsoft