Revolut API refresh token issue

Did anyone successfully get a response from the below post request?

curl https://sandbox-b2b.revolut.com/api/1.0/auth/token \
  -H "Content-Type: application/x-www-form-urlencoded"\
  --data "grant_type=refresh_token"\
  --data "refresh_token= <token>"\
  --data "client_id=<ClientID>"\
  --data "client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer"\
  --data "client_assertion=<JWT form the above JS code>"  

I always get `{"error":"invalid_client","error_description":"client_secret is missing"}curl: (6) Could not resolve host:

Please note that this is a Sandbox environment.`