2019-12-19 14:45:57,831 - synapse.access.http.8008 - 233 - INFO - PUT-906- - - 8008 - Received request: PUT /_matrix/client/r0/profile/@user:server.cloudapp.azure.com/displayname
2019-12-19 14:45:57,932 - synapse.handlers.message - 695 - WARNING - PUT-906- Denying new event <FrozenEventV3 event_id='$e_mVDdJ-rQVW25vaOgXIU3zNppPZfOCJUo5YhMQ0rTM', type='m.room.member', state_key='@user:server.cloudapp.azure.com'> because 403: Cannot force another user to join.
2019-12-19 14:45:57,932 - synapse.handlers.profile - 281 - WARNING - PUT-906- Failed to update join event for room !GstgHdhajwAvSueHan:server.cloudapp.azure.com - 403: Cannot force another user to join.
2019-12-19 14:45:57,966 - synapse.handlers.message - 695 - WARNING - PUT-906- Denying new event <FrozenEvent event_id='$157676675735pBzAC:server.cloudapp.azure.com', type='m.room.member', state_key='@user:server.cloudapp.azure.com'> because 403: Cannot force another user to join.
2019-12-19 14:45:57,967 - synapse.handlers.profile - 281 - WARNING - PUT-906- Failed to update join event for room !AvSWOczTtSmEVpjVlF:server.cloudapp.azure.com - 403: Cannot force another user to join.
2019-12-19 14:45:58,724 - synapse.access.http.8008 - 302 - INFO - PUT-906- - - 8008 - {@admin_user:server.cloudapp.azure.com} Processed request: 0.892sec/0.000sec (0.051sec, 0.011sec) (0.085sec/0.662sec/109) 3B 200 "PUT /_matrix/client/r0/profile/@user:server.cloudapp.azure.com/displayname HTTP/1.1" "curl/7.58.0" [0 dbevts]

curl -X PUT --header 'Authorization: Bearer access_token' --header 'Content-Type: application/json' --header 'Accept: application/json' -d '{ "displayname": "new name" }' 'http://localhost:8008/_matrix/client/r0/profile/@user:server.cloudapp.azure.com/displayname' -i

HTTP/1.1 200 OK
Server: Synapse/1.6.1
Date: Thu, 19 Dec 2019 14:45:57 GMT
Content-Type: application/json
Content-Length: 3
Cache-Control: no-cache, no-store, must-revalidate
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept, Authorization

{}