iPhone - not trusted certificate

I have a "not trusted" certificate that only pops up when using Spectrum WiFi Hot spots on my iPhone 11 Pro iOS 14.4.

It doesn't appear in the Certificate Trust Settings. One of my email accounts uses this Incoming Mail Server and SMTP address that appears in the certificate: boxXXXX.bluehost.com.

How do I get this certificate to stop popping up? If I turn off WiFi and just use mobile access and it continues to pop up. Only solution is to turn the phone off and on outside of Hot Spots. It only happens after a Spectrum Hot Spot tries to access my iPhone.

Any Suggestions?