Error 502 right after installation

Hi all,
I just installed a GitLab CE instance on an Ubuntu 20.04 ARM-based machine.
All went well and I managed to change the listening port from 80 to 8080 (because 80 is already in use).
When I go to the gitlab installation web page I get the error 502 - Whoops, GitLab is taking too much time to respond.

Here is gitlab-ctl status:

run: alertmanager: (pid 69145) 2570s; run: log: (pid 56018) 2855s
run: gitaly: (pid 69165) 2569s; run: log: (pid 35933) 5802s
run: gitlab-exporter: (pid 69183) 2569s; run: log: (pid 55941) 2873s
run: gitlab-kas: (pid 70309) 2342s; run: log: (pid 36207) 5790s
run: gitlab-workhorse: (pid 69197) 2568s; run: log: (pid 36445) 5725s
run: logrotate: (pid 69216) 2568s; run: log: (pid 35886) 5813s
run: nginx: (pid 70319) 2341s; run: log: (pid 36464) 5719s
run: node-exporter: (pid 69232) 2567s; run: log: (pid 55920) 2879s
run: postgres-exporter: (pid 69239) 2566s; run: log: (pid 56068) 2847s
run: postgresql: (pid 69256) 2566s; run: log: (pid 36074) 5796s
run: prometheus: (pid 69275) 2565s; run: log: (pid 55991) 2859s
run: puma: (pid 75317) 43s; run: log: (pid 36366) 5738s
run: redis: (pid 69299) 2565s; run: log: (pid 35902) 5806s
run: redis-exporter: (pid 69309) 2564s; run: log: (pid 55969) 2865s
run: sidekiq: (pid 70248) 2360s; run: log: (pid 36392) 5732s

Thank you to all.