radosgw start failed due to handle_auth_bad_method

Regarding https://tracker.ceph.com/issues/45142 reported against nautilus,

2020-04-19 09:05:05.421 7fe2eeea9700 -1 monclient(hunting): handle_auth_bad_method server allowed_methods [1] but i only support [2,1] failed to fetch mon config (--no-mon-config to skip

I don't understand why this negotiation would fail. Are there any known bugs here? Or can anyone explain this? Thanks, Casey