Bad Gateway accessing Vaultwarden via domain (Nginx Proxy Manager)

Apps and Virtualization
1

Hi all,

I’m running into an issue accessing my Vaultwarden instance through my domain and could use some help troubleshooting.

Setup:

TrueNAS Apps (Vaultwarden + Nextcloud)
Nginx Proxy Manager handling external access
Domains:
nextcloud.mydomain.net → working correctly
vault.mydomain.net → not working (502 Bad Gateway)

Issue:
When I try to access Vaultwarden via vault.mydomain.net, I get a 502 Bad Gateway error.

However:

I can access Vaultwarden internally using the Web UI button in the TrueNAS Apps screen
Nextcloud is working fine externally through Nginx with a very similar proxy host setup

What I’ve tried:

Configured the Vaultwarden proxy host the same way as Nextcloud
Deleted and recreated the proxy host multiple times
Confirmed Vaultwarden is running and accessible internally

Where I’m stuck:
I’m not sure what I did differently to get Nextcloud working, and I can’t seem to replicate that success with Vaultwarden.

Question:

Is there something specific about Vaultwarden’s internal port or networking I should be aware of?

Any guidance on what to check next would be really appreciated.

Thanks in advance!

2

Public Domain ist set correctly in the vaultwarden docker yaml ?
X-Forwarded-For is set in the frontend of the proxy ?

3

Bad gateway means the app service/server is down.

(Or, the reverse proxy config is wrong).

4

I can get to VW via the ip https://xxx.xxx.xxx.26:30067, and it gives me a login screen. Nginx is set to take vw.mydomain.net to xxx.xxx.xxx.26 and port 30067. Right now, I am getting “Web server is returning an unknown error Error code 520”

Maybe I should remove it and try it all again.