setupProxy.js errors are silently dropped

[dinvlad]

Closing, looks like there's already a PR for this #10652

[micahjsmith]

This appears to still be an issue, and shouldn't have been marked as closed/completed since the PR was never merged.

With react-scripts 5.0.1, errors in setupProxy are still silently dropped for me and it causes the devserver to not bind to the port (giving E_CONN_REFUSED). This appears to be what is referenced by #11860 (comment)