Fixing [400] An error occurred while sending an authentication request to the vCenter Single Sign-On server

So After the last two blog posts about fixing vCenter7’s access issues due to it’s due certificate monument work flows. I was greeted with this error when trying to sign into the web UI on vCenter.

[400] An error occurred while sending an authentication request to the vCenter Single Sign-On server- An error occurred when processing meta data during vCenter Single Sign-On setup:the service provider validation failed. Verify that the server URL is correct and is in FQDN format, or that the hostname is a trusted service provider alias.

After a a quick google search I found yet another VMware KB discussing it.

 Resolution
This is an expected behavior.
VMware vSphere 7.0 enforce FQDN or IP address reverse resolvable to FQDN to allow authentication for Single-Sign on.
Greeeeeeeeeeeeeeaaaaaaaaat! Thanks VMware, just another example of security destroying functionality.
What did I do? Exactly what it stated, I navigated to the WebUI URL using the hostnames Fully Qualified Domain Name E.G: Hostname.domain.end
Cause I was attempting to access it just by just the hostname as domain info was being auto resolved by the domain suffix during queries.