synapse first user registration error

root@parustrans:/home/bereska# register_new_matrix_user -c /etc/matrix-synapse/homeserver.yaml https://localhost
New user localpart [root]: admin
Password: 
Confirm password: 
Make admin [no]: yes
Traceback (most recent call last):
  File "/usr/bin/register_new_matrix_user", line 20, in <module>
    main()
  File "/opt/venvs/matrix-synapse/lib/python3.6/site-packages/synapse/_scripts/register_new_matrix_user.py", line 221, in main
    args.user, args.password, args.server_url, secret, admin, args.user_type
  File "/opt/venvs/matrix-synapse/lib/python3.6/site-packages/synapse/_scripts/register_new_matrix_user.py", line 134, in register_new_user
    user, password, server_location, shared_secret, bool(admin), user_type
  File "/opt/venvs/matrix-synapse/lib/python3.6/site-packages/synapse/_scripts/register_new_matrix_user.py", line 54, in request_registration
    nonce = r.json()["nonce"]
  File "/opt/venvs/matrix-synapse/lib/python3.6/site-packages/requests/models.py", line 900, in json
    return complexjson.loads(self.text, **kwargs)
  File "/opt/venvs/matrix-synapse/lib/python3.6/site-packages/simplejson/__init__.py", line 525, in loads
    return _default_decoder.decode(s)
  File "/opt/venvs/matrix-synapse/lib/python3.6/site-packages/simplejson/decoder.py", line 370, in decode
    obj, end = self.raw_decode(s)
  File "/opt/venvs/matrix-synapse/lib/python3.6/site-packages/simplejson/decoder.py", line 400, in raw_decode
    return self.scan_once(s, idx=_w(s, idx).end())
simplejson.errors.JSONDecodeError: Expecting value: line 1 column 1 (char 0)