I have this issue while trying to consume an API(running on Apache Catalina), hosted on the same server running on Windows, where I am trying to run the React. I have setup setupProxy.js, declared Proxy in the package.json (“proxy”: “http://localhost:3000”,).

I had tried fetch, Axios and XMLHttprequest as well.

I initially had problems in consuming this API, but all of a sudden I have this “431 (Request Header Fields Too Large)” in the console. Any advise is much appreciated

Here are the things I tried (for 431 error)

• clearing the cache.
• Run in Incognito mode
• Restarted the Chrome

Expecting to send a request to the server(hosted on the same server) and get a response.