I recreated a certificate, but a reboot with version 85 gave me a "selftest OK" again, but still a blank screen.

Rebooted into version 80 and I'm back in...

While the ESX was still off, I removed the IP restrictions on all targets, so they were set to "ALL" on "Allowed" and disabled the CHAP authentication for all of them.

But still, no luck with adding the target portal to any MS iSCSI initiator...