We are currently in the process of configuring a Pega OAuth 2.0 client registration rule to provide an authentication to salesforce end. During the configuration we were encountered an issue related to SSL certificate, it appears that there might be an issue with certificate on the server.

https://xxxxx.yyyyyy.com/prweb/app/SMAll/eizqsRF0AtzSDYuWNSKLx9sBY2D4eYuc*/!STANDARD

Picture1

Also, It can access using url as above mentioned, https://xxxxx.yyyyyy.com/prweb/app/SMAll/eizqsRF0AtzSDYuWNSKLx9sBY2D4eYuc*/!STANDARD

But when generating a OAuth2.o Client registration rule, it automatically getting as follows,

Picture2

Cannot proceed with http

Have you got any idea of not getting https?