Unable to add independent VMware esxi server

I had the exact same issue last week. I added the ESXi host from the command lineand was added with no issue.

"tpconfig -add -virtual_machine <virtual_machine_name> -vm_user_id <user ID> -vm_type <virtual_machine_type> -requiredport <IP port number> -password <password>

<virtual_machine_name> = ESXi hostname

<user ID> = account that has required priviledges i.e root

<virtual_machine_type> = 2 (for ESXi Host)

<IP port number> = 443

<password> = password for root account