Struggling with GET_REQUESTS url.

(I'm doing this via Python, but that shouldn't matter too much.)

I make a POST request to this URL:

[base_URL]/api/json/request?scope=sdpodapi&authtoken=$token&OPERATION_NAME=GET_REQUESTS&I NPUT_DATA={operation:{Details:{FROM:0,LIMIT:100}}}

This URL totally returns 100 tickets, regardless of status or anything.

I make a POST request to this URL:

[base_URL]/api/json/request?scope=sdpodapi&authtoken=$token&OPERATION_NAME=GET_REQUESTS&I NPUT_DATA={operation:{Details:{FROM:0,LIMIT:100,FILTERBY:"Group - Name"}}}

And I receive an error:

{"operation":{"name":"GET_REQUESTS","result":{"status":"Failed","message":"User does not have this permission","error_code":4002}}}

The group I'm filtering by is one I created for myself. The token is clearly working, as it returns the 100 tickets in the first URL there. I have administrator access to our SD instance. The group type doesn't appear to matter. [eta] The only group that works is "All Requests".

What am I doing wrong?