Hello, I have two crm2015 servers 1 dev and 1 prod running with IFD. My dev server has been working fine internally and externally. I just completed the prod install and setup claims based authentication and suddenly cannot access CRM through IE internally on either server. I am prompted by IFD for my credentials but after that I get 400 error. If I log in with firefox I can successfully authenticate and get to both CRM boxes. I believe I had this issue when I installed the dev box and resolved it by an spn on the crm server to the ifd server however this does not seem to work this time?
I also found this error any help would be appreciated.
The Kerberos client received a KRB_AP_ERR_MODIFIED error from the server fed2015. The target name used was HTTP/ifd.corp.xx.com. This indicates that the target server failed to decrypt the ticket provided by the client. This can occur when the target server principal name (SPN) is registered on an account other than the account the target service is using. Ensure that the target SPN is only registered on the account used by the server. This error can also happen if the target service account password is different than what is configured on the Kerberos Key Distribution Center for that target service. Ensure that the service on the server and the KDC are both configured to use the same password. If the server name is not fully qualified, and the target domain (CORP.xx.COM) is different from the client domain (CORP.xx.COM), check if there are identically named server accounts in these two domains, or use the fully-qualified name to identify the server.
I ran "setspn -A HTTP/$servername$.$domain$.com.au $username$" and it corrected the issue.