I'm using react to build a web application with an API. The API is on localhost:3000 and the react app on localhost:5000.

Sometimes when the server reloads I get this error message in the terminal:

[1] Compiling...
[0] [nodemon] starting `node server.js`
[1] Compiled successfully!
[1] Proxy error: Could not proxy request /api/auth from localhost:5000 to http://localhost:3000/.
[1] See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (ECONNREFUSED). 

It seems like the app works fine with it, it does say it compiles successfully and it's working just fine with the database. I thought maybe the problem was that is was contacting localhost:5000 instead of http://localhost:5000/, but I don't know how to change that.

What is that error and why am I getting it?