Selfhosted

Hello Self Hosters! I am new-ish... got Jellyfin working great with tailscale remote access! I love it! I keep getting deeper into this stuff and geeking out... really excited to add my next service: Self-Hosted Nextcloud.

Would someone kindly walk me through setting up reverse proxy to my stuff with Caddy? I really just want HTTPS support, as my media files are one thing, but hosting all my personal info/docs on NextCloud is quite another thing to potentially expose....I want to make sure I harden properly, and HTTPS is clearly a part of that, even if I'm running a tailscale VPN. I have done my best following the docs/tutorial so far, but I've hit the wall with this "start" page.... Here's what I've got:

• pointed my domain "A" DNS to my website as a sub-domain... so my address in caddyfile is "sub.mydomain.com"
• I've installed caddy directly on my unbuntu server, but I admin my Jellyfin (and eventually Nextcloud) with Docker via CasaOS interface... is this a problem? Do I need to run Caddy in docker too?
• I've followed the instructions on this start page and I still only get the startpage at "sub.mydomain.com"
• my tailnet server IP address is what I'm using for the reverse proxy... that's correct, yes?
• So many things/guides just say "reverse-proxy --to ..." but when I do that, I get an error saying port 80 is 'already in use' I have combed my configs & devices on my router...nothing is using port 80 that I can see. Ports 80 and 443 ARE forwarded/open, before you ask! -My next big step in this journey is piHole, so if this will interfere/interact with that in some important way, I appreciate the heads-up mightily!

Thank you in advance, I appreciate it!

EDIT! - CasaOS uses 80 as default gateway, turns out! So, switched that... now Caddy is starting properly... STILL can't get the 'welcome' page to go away.... still a problem with my caddyfile I suppose.