I can access Vaultwarden from my domain on an external network but not on my local network. What am I doing wrong?

[BokChewy]

I see that I'm not the first person to have a similar issue, I've tried to learn through the other posts but I think I'm thoroughly stumped here. This is my first time trying to self host something so please bear with me. I've watched a few Youtube tutorials and they've gotten me this far. I'll list the steps I've taken so far and as non compromising information I can.

I'm running this off of a repurposed tower PC running ubuntu server 22.04.3 LTS.
It's connected directly to my router via an ethernet cable. (sorry if this is useless info, just wanna be thorough)

• installed the latest versions of docker, docker compose, and portainer.
• installed nginx proxy manager
• port forwarded ports 80 and 443 on my network router
• bought a domain via namecheap and set up an "A Record" subdomain that's tied to my host machine's external IP address.
• installed vaultwarden

my vaultwarden docker compose file:

services:
  vaultwarden:
    image: vaultwarden/server:latest
    container_name: vaultwarden
    restart: unless-stopped
    environment:
      DOMAIN: "http://xxx.xxxxx.xxx"
    volumes:
      - /opt/vw:/data
    ports:
      - 127.0.0.1:8080:80

(the youtubers I watched had wildly different things in their compose file so I just went with what was on vaultwarden's github page instead. It yelled at me for putting portainer and vaultwarden both on external port 8000 so I changed the port in my vaultwarden compose file to 8080 instead.)

• created a proxy host on nginx with the domain I reserved. The scheme set was http, destination set was the IP address of the vaultwarden container, port set to 80. I also made sure to request an SSL certificate from letsencrypt which went through successfully.

lo and behold; at this point, I've been trying to get into the vaultwarden webUI via my windows laptop on the same local network through the domain I reserved but it keeps giving me "This site can't be reached blah.blah.blah refused to connect" etc. I clear my cache, switch browsers, wait a day, nothing works. THEN today, I'm out shopping and, for kicks, I decide to try the domain on my phone (while on data). BOOM! I'm in. It takes me straight to the Log In screen. I got super excited and came home to login on my laptop but then it gave me the refused to connect page again. At this point I'm fairly confident that It's working, but for some reason it won't let me connect on my local network; only on an external connection.

What's goin on??

[BokChewy]

should I ask somewhere else?

[kpfleming]

You can, you can also just have some patience, as everyone who answers questions here is a volunteer and you asked in the middle of a weekend as well.

The symptom you are describing is probably the result of configuration in your router; many home/small-business routers don't handle internal access to their own external IP address very well, and that's what you're doing here. It's definitely a network traffic routing issue and not related to Vaultwarden itself, as you've proved by successfully accessing it from another network.

[BokChewy]

Sorry if my question came off rude! I was worried that my problem had nothing to do with VaultWarden and it seems that was the case. You folks are doing amazing work providing support here and I hope you have a great day!