Wiederaufbau fehlgeschlagen - FAILED TO BOOTSTRAP

[Firepup650 (Firepup Sixfifty)]

From another topic on this exact issue:

Update Fails with Unexpected Error During Rebuild

Jay had the same issue Rebuild failure: "extconf failed, exit code 1" -- due to old Docker?, but I don’t know if he figured out the issue ultimately. @TroyaNO Just in case, can you try to type git pull before trying again ./launcher rebuild app?

Update Fails with Unexpected Error During Rebuild

I decided that it was an old Docker, though that didn’t really make sense. But I bet this has been on the same vm since 2018 and the os is out of date. So what I would do is spin up a new droplet and Move a Discourse site to another VPS with rsync.