OME 2.2 - ESXi - No health status

I am trying to get OpenManage Essentials 2.2 to report health of ESXi.

A server with ESXi 5.1 and OMSA 7.4 is showing health
Servers with ESXi 6 and OMSA 8.3 only show a grey question mark.

I cannot find any documentation stating which versions of ESXi and OMSA is compatible with OME 2.2.