Hi Paulo
We recently dealt with a similar error. The iframe problem is due to the fact that modern browsers will block directing to a different domain within a frame. Please take a look at
http://stackoverflow.com/questions/25098021/securityerror-blocked-a-frame-with-origin-from-accessing-a-cross-origin-frame
for instance
VSphere 6 login form is based on iframe.
This iframe is always redirected by vCenter server to the URL that includes FQDN configured in vCenter and may be different from that which is configured in PAM.
I'm suggesting to navigate to vSphere 6 login page from native browser (FireFox or Chrome), open "Developer tools" (F12) and then look in Network tab at URL to which your browser is redirected and set proper FQND in device configuration on PAM.
You may as well use fiddler to do the same. If the above recommendation does not help, I would suggest you to open a case with support as this will require further investigation and likely Engineering involvement.