Getting a 406 Error Code - What’s Causing It and How Do I Fix It? or Why Am I Seeing a 406 Error Code

Ugh, 406 errors are the worst. Had this happen when my client’s CMS was forcing weird headers.

Two things that worked for me:
1. Forcing the Accept header in PHP: `header('Accept: application/json');`
2. Using curl to test the request directly—sometimes browsers add junk headers.

If you’re on WordPress, the "Rest API" plugin can help debug too.