Can you check domain controller certificate on Active directory by following below steps
1. Click Start > Run > MMC > OK.
2. In the Console 1 window, click File > Add/Remove Snap-in > select Certificates > Add > select Computer Account > Next > Local Computer > Finish > OK.
3. Expand Certificates, expand Personal, click Certificates.
Check whether you have a certificate with Template as "Domain Controller". If this certificate is not present follow below steps to create domain controller certificate
1. Right-click Certificates, then click All Tasks > Request New Certificate.
2. In the Certificate Enrollment wizard, click Next.
3. Select Domain Controller, and click Enroll > Finish.
After this you can check active directory login on iDRAC