Unable to lookup server keys

[thelazyoxymoron]

I'm trying to join a public channel on matrix.org server using my sefhosted server running dendrite. Joining fails with the following error:

level=warning msg="Failed to request keys from fetcher" context=missing error="gomatrixserverlib: unable to lookup server keys: contents=[] msg=Failed to POST JSON (hostname \"matrix.org\" path \"/_matrix/key/v2/query\"): code=520 wrapped=" fetcher="perspective server matrix.org

[blind-oracle]

Same here for me. Calling the URL with some curl works fine, so the connection works.