ArcGIS Enterprise 11.0\Pro 3.0.1: Data registration fails and ends up with “error validation with server”,

Question

As per the screenshot below, despite the fact that the ArcGIS Server is correctly federated, data registration fails and ends up with “error validation with server”.

What might be the issue here?

JamalNUMAN · Answer

I manage to apply the registration from the ArcGIS Server manager and with few clicks here and there it appears to work fine as per the screenshots below.

Not sure the registration is an issue in Pro. It has never been an issue in ArcMap

ryanuthoff · Answer

Do you have a valid SSL certificate (not the default Esri self signed certificate) configured with Portal/Server? I experienced the same issue a couple weeks ago and that's what fixed my issue.