Response 406 Not Acceptable from the API

[BuffChris]

I receive the 406 error message when my application sends this request https://cwms-data.usace.army.mil/cwms-data/timeseries/filtered?name=Mount%20Morris-Tailwater.Elev.Inst.30Minutes.0.GOES-NGVD29-Rev&office=LRB&begin=2026-04-01T13:32:56.960Z&end=2026-04-22T13:32:56.960Z

when I put it in the browser it works fine, I'm debugging the solution in Visual Basic, it's a legacy program, I think it is in mostly C#

Any suggestions about how to fix the request so it responds back with a JSON without error would be much appreciated!

[MikeNeilson]

Most likely it would be an incorrect accept header. Accept: application/json should get you the preferred default format.

That said there should be an incident identifier in the error response, we can use that to track look up a more detailed log entry about the issue.

If there's no identifier than it may a matter of how legacy. it's all TLS so if HTTP 1.0 and no Host header, the WAF would get confused.