Review mod_security logs to see if a firewall is blocking the request.
As outlined in the Airbrake documentation and this YouTube video , resolving 406 errors requires investigating both the client request and server configuration:
The server understands the request but cannot provide the data in the requested format. 406 mp4
A client may request JSON, but the server only offers XML, resulting in a 406.
The server may reject requests from specific browsers or user agents that it considers "not acceptable". Troubleshooting and Solutions Review mod_security logs to see if a firewall
The error occurs when a user agent (e.g., a web browser) sends a request with specific headers—such as Accept , Accept-Charset , or Accept-Language —requesting a particular format, but the server is unable to provide a response that matches these criteria. HTTP Status Code:
The 406 error frequently arises due to a mismatch between requested and available content types, according to Error404.atomseo.com . The server may reject requests from specific browsers
Ensure the client is requesting data types ( Accept header) that the server actually provides.