Symptoms
Though there isn't any IIS configuration to use HTTPS binding for Smartforms site, there will be an error message "There is this problem with this website certificate" shown on webpage.

Diagnoses
We will redirect the traffic to Identity Site and by default that is using HTTPS binding.

Resolution
This certificate error was resolved by modify Claim Issuer Window STS entries. This can be done either at Database (aK2]. Identity].nClaimIssuer] table) or Security Forms (https://ttSmartformsRuntimeURL]]/Runtime/Runtime/Form/Manage+Issuers/)
Blackpearl Server service restart is required