Just did a quick try on vultr and seems to be a firewall issue as everything seem to stop at
that config.
I can’t create a new putty login after that.
P.S. Finally got an error
wget https://rc.software.virtualmin.dev/virtualmin-install-7.7.3.sh
sh virtualmin-install-7.7.3.sh
this one works 
it was yellow on etckeeper and awstats whatever that implies.
I had same error. putty works fine though.
Yeah I noticed that, no idea.
I put the first install I 1gig memory with slow to error.
Second try on 4gig memory error happened straight away. Might have been the low resources.
I was messing with 1Gb Rocky 9 on a VPS a while back, performance was terrible.
Once I created a small swap file it worked really well. Up to that point, the VPS was thinking of pulling the 1Gb option for Rocky due to performance.