Hosts accessible via vSphere client.
Accessing its https://ipaddress shows the usual ESXi welcome page.

In SDP, I've created VMware credentials.

Upon scanning the server via Vmware, the following error shows up when using both credential were used:

Connection to SSH Service in the workstation failed.

ESXi 5.0.0 scanned normally. Error only ESXi 5.5.0

Please advise, support file available upon request.
Thank you in advance.