Internal Certificates not trusted by iOS after Sept 1st, 2020 with validity period greater than 398 days..
The following post indicates that iOS devices will not trust certificates after Sept 1, 2020 with a validity period greater than 398 days for Root CAs pre-installed devices. This article also indicates that user or administrator added root CAs will not be affected.
About upcoming limits on trusted certificates - Apple Support
We took this to understand that our internal certificates from our company would not be affected, however this is not true. We found a workaround by setting a browser setting to trust all certs, however, some apps like Power BI do not work with the workaround in place. Is there any confirmation Apple can give that this would also affect the trust of certs not issued by public Root CAs but our own internal Root CA?
iPhone XR