I recently ran into this error without changing anything in my setup. I get the error “504 Gateway Time-out” when trying to access my nextcloud instance at sub.domain.com, both from local network and from outside. I can access https pages in domain.com (apache running on host without docker) and ssh into the server. I have rebooted both the server and the router. My DDNS is up to date.
Where to go from here?
EDITED TO ADD: I tried switching to swag, but the situation is the same. Swag log is here.