Auth Proxy Authentication don't work

hey people,
i use auth proxy in connection with a reverse proxy in node.js
my application runs on port 4000. Grafana on 3000.
I can navigate to the proxy and everything else too, but not save it.

the logs say:
t=2018-12-16T21:55:51+0100 lvl=info msg=“Request Completed” logger=context userId=5 orgId=1 uname=try method=POST path=/api/dashboards/db/ status=400 remote_addr= time_ms=120043 size=153 referer=http://localhost:4000/dashboard/new

In defaults.ini, I set it up that way:
enabled = true
header_name = X-WEBAUTH-USER
header_property = username
auto_sign_up = true
ldap_sync_ttl = 60
whitelist =

have I forgotten which dependencies?