VMware: VCVA: Invalid Hostname. FQDN is required for joining a domain.
Last week I upgraded my lab to vSphere 5.5, during the install I entered the hostname to configure domain authentication but I received this error:
Error: Invalid hostname. FQDN is required for joining a domain
Solution:
Goto Network > Address > Hostname
Add the domain information in the hostname box, sample:
After this change I was able to configure AD authentication:
Solved for me too