VMware ESXi 6.7 fails to connect VM web console with "You have reached the maximum number of connected consoles: 40. Please contact your administrator."
I tried disconnecting all the open session to vCenter which never helped.
I also tried to restarting the VM which also never helped. I managed to narrow it down to being a problem with the VM and not vCenter, because the web console was working for other VM's.
The fix for me was to shutdown the VM, remove the VM from the vCenter inventory (don't delete from disk), then Register it from the datastore again. Then the error disappeared.