Unable to logon to Reporting Service with a domain account

I have a couple of times recived problem to logon to Reporting Service after I have done an installation. I have now read the installation manual and finds out that the account running RS need to be trusted for delegation. I have not known that before and I have done plenty of installations without this when I know there is no need for Kerberos. Today I get really frustrated and tried to solve why it was not possible to logon to the server. It worked ok with my local admin account but not the domain account with local admin rights. I run some other reporting instances on same server and they works well so I find it really strange. In BOL I find that you must be sure that the key rswindowsnegotiate is added in the RsReportServer.config file to enable Kerberos. Hmm why not remove this then to use NTML instead. I compared the working RS instance with the new one and it was not there in the working RS, so I just removed it and restarted the RS. This did magic, no I can logon to RS. Another solution should off couse be to setup the service account in a proper way but that is another question. So to make a RS work you have to setup the service account for RS to use Kerberos or be sure to remove the rswindowsnegotiate from RsReportServer.Config file