[Help Wanted] "NetworkError when attempting to fetch resource" (Self Hosting Error)

[Doormat7563]

Describe the issue
Every time I try to spin up a new Standard Notes instance since about Q1 of 2024 I keep getting this "NetworkError when attempting to fetch resource" error.

Steps to reproduce the behavior:

1. I go through the entire process of spinning up a new instance.
2. I try to create an account/login from different devices.
3. And I get "NetworkError when attempting to fetch resource" on the web app or "Unknown error" on the MacOS app. Or it will accept the credentials, let me into the account then request I authenticate again every 5 seconds.

Expected behavior
The deployment is supposed to accept the new credentials, create said account; then sign me in. Its not doing that. And Ive had to fall back to app.standardnotes.com for my backend instead.

Desktop (please complete the following information):

• OS: Sequoia 15.0.1
• Browser: Mullvad Browser, Safari
• Version: 3.195.13

Smartphone (please complete the following information):

• Device: iPhone 14 Pro Max
• OS: iOS 18.2.1
• Browser: Safari, Brave Browser
• Version: 3.194.11

Additional context
This instance is running on a VPS using Ubuntu 24.10. I've tried this many times in many different ways. I even found out it could be a CORS issue so I rewrote my NGINX config and i've still had no luck. If anyone can provide guidance I appreciate it. :(

[piit79]

Do you by any chance see any "Cookie <cookie_name> rejected for invalid domain" errors in the Developer tools Console in the web app when logging in? If you do, this should help: standardnotes/server#1068

tl;dr: You need to set COOKIE_DOMAIN=<your-API-host> in the .env file for the cookies to work correctly.