I've been running ESXi 5 on an old Dell server for several years, and installed one Centos 7 VM.
After a recent power cut, the VM didn't restart, and I couldn't log in remotely to the host to restart it. I rebooted the host machine by switching if off and on again.
I then tried to log in to the Management Console using a browser, and succeeded just once, from my phone, giving me the opportunity to restart the Centos virtual machine. So it's working, as designed, as a Plex Media Server.
But before and since the one connection from my phone, I can't login from any browser, or indeed from my phone again, to the management console of the host.
I just get the error message in the title.
I've tried both Chrome Version 78.0.3904.87 (Official Build) (64-bit) (but it is updating as I write this) and Safari 13.0.3 (14608.3.10.10.1), both running on Mac Mojave.
And now when I try again in Safari, using the same credentials that worked on the phone, it just won't connect, saying I have the wrong password.
Do I have to connect a keyboard and screen to the ESXi host to re-establish a connection and/or update ESXi? The Dell is old enough that it won't work on ESXi 6 or later. AFAIK.
If/when I do get a connection, I would like to set the VM also to restart in the face of a power failure, but a) I can't access it, and b) the instructions I found to set the properties of the VM to auto-restart don't match what I saw on the screen the one time I did have the connection to it