I've configured vRA 7 to use LDAP > AD Authentication. Despite using a subtree of the directory for searches the login latency is crazy (over 20 minutes). Obviously login is cache'd as after the first attempt its quick after this. Is anyone else here using vRA 7 with AD Authentication? I'm using SSL on Port 636.
Previously I was using SSO (Legacy) and this was quick. However I was having other issues with this since the vRO > vRA 7 Plugin is no longer able to enumerate the 'composite blueprints' folder meaning I can no longer use the WFStubs which previously were working perfectly previously. Two vRA 7 environments I have developed this issue on the same day.
I was having a similar experience as you were (long wait time) only for it to come back and say that it failed to connect to the AD Server. For me the problem was simply changing the port number and it returned almost instantaneously. I only used the non-ssl route so I can't help you there but most definitely check your connection and make sure the ssl port is not being blocked by a firewall.