[HPM] Error occurred while trying to proxy request /api/courses from localhost:4200 to http://localhost:9000 (HPE_INVALID_CONSTANT)

[KoenMeijer]

When I try to start the application I get the following error message: [HPM] Error occurred while trying to proxy request /api/courses from localhost:4200 to http://localhost:9000 (HPE_INVALID_CONSTANT) (https://nodejs.org/api/errors.html#errors_common_system_errors)

I tried to use another port, and switched localhost for 127.0.0.1 but without success. What can I do about it?

[harshalslimaye]

@KoenMeijer Try running npm run server along with npm start in two separate terminals.