I had a similar problem - the auto-renew didn’t work.
My setup had nginx proxy manager running on an unRaid box using macvlan network, and connected to unifi switching. What the problem was for me was the NPM box wasn’t able to get external network connectivity so like you I ended up reinstalling it all over again.
Problem kept happening, so in the end I just ditched it all & went CaddyV2 and (touch wood) so far no problems.