Yeh had the same issue I went into skyline health diag > left side click on vSphere management and remove all the vspheres
then go to vsphere make sure the plugin has been successfully undeployed (you should see a blue bar) then readd the vsphere servers with the FQDN (previously was IPs). with the FQDN you may get a warning about Skyline not able to verify the server but continue.
for one server i had to do it 2 times before it worked
hope it helps