Similar issues have been seen in the past where load balancing with Windows authentication is being used, further details can be found here:
Also, upgrade check failures have previously been caused by an update to the password for the configuration account, could you verify the credentials set for each of your database connections:
I would also recommend verifying that there are no variances for each of your servers as follows:
Thx a lot.
The first article brings us the helping resolution.
Our problem was. We had the SPN of the service account beside the Netscaler DNS also added the 2 AppSense Server names.
After we deleted the 2 Hostnames, the login worked fine.