The problem is solved, the error was in the IP-Address Settings.
Hi, so I have problems with IPMI on the R610. I can access the login page of the iDRAC6 webinterface, but when i enter login data it connects me again on the login page (it's exactly the same with wrong data, also does not show that they are wrong). "ipmitool" works properly.  
Can access iDRAC6 webinterface, but can't login