my mistake I forgot to point out that you are missing a client-id header as got focussed on the wrong auth header prefix
curl -X GET 'https://api.twitch.tv/helix/users/blocks?broadcaster_id=141981764' \
-H 'Authorization: Bearer 2gbdx6oar67tqtcmt49t3wpcgycthx' \
-H 'Client-Id: wbmytr93xzw8zbg0p1izqyzzc5mbiz' \
Additionally if you update your code to spit out the body of the response and not just the HTTP Code then the error message contained in the response should tell you the problem.
The HTTP Code is half the information