@makemrproper I have seen this as well . I am not sure what's causing this. But I will keep this thread open, just in case someone else hits this. I has to restart docker to "fix this" (systemctl restart docker)
If you have a floating IP (in DigitalOcean lingo), elastic IP (AWS) or equivalent, you can make Cloudron use the floating IP (Network -> Interface -> Enter the floating IP). Then you can restore Cloudron to another server, and then when restoring is done, you can switch the floating IP to this new server.
@p44 The MySQL database in Cloudron is shared by all the apps. In MySQL 5.7.5+, they changed the behavior to have ONLY_FULL_GROUP_BY to be the default to be more compliant. Disabling this at the server level will cause issues for other apps.