Secure channel between the DC’s broken:
Follow these steps to reset KDC password :-
1. Stop the Key Distribution Center (KDC) service on Server2. To do so, open
a Command Prompt, type net stop KDC, and press Enter.
2. Load Kerbtray.exe. You can do so by clicking Start, clicking Run, and
then typing c:program filesresource kitkerbtray.exe and pressing Enter.
You should see a little green ticket icon in your system tray in the lower
right corner of your desktop.
3. Purge the ticket cache on Server2, right-click the green ticket icon in
your system tray, and then click Purge Tickets. You should receive a
confirmation that your ticket cache was purged. Click OK.
4. Reset the Server domain controller account password on Server1 (the PDC
To do so, open a command prompt and type: netdom /resetpwd /server:server2
/userd:domain.comadministrator /passwordd:password, and then press Enter.
5. Synchronize the domain. To do so, open a command prompt, type repadmin
/syncall, and then press Enter.
6. Start the KDC service on Server2. To do so, open a command prompt, type
net start KDC, and press Enter. This completes the process, and the domain
controllers should be replicating success-fully now