I am unable to join my vSphere to my active directory domain. The vSphere domain is "domain.local" and our AD domain is also "domain.local". Is this allowed?
Agreed with @Alex_Romeo. Furthermore, Active Directory (Integrated Windows Authentication is apparently becoming deprecated in newer releases. You'll be required to use the Active Directory over LDAP option instead. Since you've integrated recently, I might suggest to "convert" over to the latter instead to avoid having to do it in the future.