Http request 404 error

Hey guys,
when I’m trying to login using my application I get 404 not found error every time.

POST 404 not found error

tried fixing that by installing cordova-plugin-whitelist and adding to my config.xml but it didn’t help, I see two requests with errors: the first one is

POST 301 Moved Permanently

The second one is

GET 404 not found

Can you please help me understand what am I missing?
I’ve also got this thread at StackOverflow. I’ll be happy if any of you can take a look:

You need to show some code. Login to what?