Hi!
This works great on https://query.wikidata.org/, but when I enter it in my local installation, I get an error with this line in my stack trace:
java.util.concurrent.ExecutionException: java.util.concurrent.ExecutionException: java.lang.IllegalArgumentException: Service URI http://wikiba.se/ontology#mwapi is not allowed
Your local installation seems to be old version. Please check out the newest one from github. MWAPI service should be whitelisted automatically in the new code.