Subscribe is not working with thingsboard

hi…i am connecting thingsboard server by using MQTT api’s…and i was successfully published my data to the server by using the api’s like…v1/devices/me/telemetry…
but i am unable to subscribe to thingsboard by using RPC api like… v1/devices/me/request/+…
and by using ATTRIBUTES also like… v1/devices/me/attribute
when i am varying the widgets i am not getting any data from the server…