Ah.. I got this:
solr-mailcow_1 | System memory less than 2 GB, skipping Solr…
I have 2 GB VPS but I am not sure if they are referring to 2GB avail?
root@localhost:/opt/mailcow-dockerized# free -h
total used free shared buff/cache available
Mem: 2.0G 1.7G 89M 4.1M 189M 130M
Swap: 2.0G 889M 1.1G
root@localhost:/opt/mailcow-dockerized#