I was patching esxi hosts and had 1 host that was waiting to go into maintenance for hours because of a stuck vsan resyncing process (something with a stale object). After we fixed the vsan issue we could put the host into maintenance again but VCF had decided to put the host into an ERROR state. below in the picture you can see an example of good hosts, 1 will be in error state but i did not have a screenshot saved of that unfortunately.
to fix this you will have to go into the database of the SDDC Manager.
DO NOT FORGET TO MAKE A SNAPSHOT OF YOUR SDDC MANAGER FIRST!
psql -h localhost -U postgres
c platform
select id, hostname, status from host;
update host set status = 'ACTIVE' where id = 'HOSTID';
This will connect to the database and then list all the hosts with their status and finally you can run the last command with the correct hostid (you can find this by also clicking on the host in sddc manager and copy it from the URL bar). After this wait at least 15 minutes before retrying the update process and it should start working again.
the blog i used to get this good info from and apparantly still works on 4.5.1:
https://www.vsam.pro/sddc-manager-doesnt-want-to-start-or-retry-an-update-vcf-3-10/
The original article was posted on: www.hollebollevsan.nl