How to use auto login for dashboards in checkmk

hi Guys,

I used your manual and this thread to configure this in our Office and Display a Dashboard on a Monitor for everybody in the IT-Department.
Now i upgraded to CMK 2.2.0 and since than the autologin doenst work anymore.-
If you try to open the Dashboard via this link:

http://Server_IP/Instancename/check_mk/login.py?_origtarget=/Instancename/check_mk/dashboard.py?name=simple_problems_stw&_username=kioskuser&_password=kioskpassword&_login=1
(i replaced all interna like the name of the instace, credentials in this)

you get following message:

(MEthod not allowed)

The Credentials are filled in anyway and you can click on Login.
This leads to the desired Dashboard.

Any solution to this?

Thx in Advance

Regards
Gregor