How to Fix – Event ID: 1121 Source: NTDS

The format of the schedule attribute of the following object is unrecognizable.

As per Microsoft: “The format of the specified object’s Schedule attribute is not recognizable. A default schedule will be substituted. This event will continue to occur until the Schedule attribute on this object is corrected”.

Have you made any changes in AD sites and services since promotion?

Some times this happens due to DNS. Remove invalid DNS record and see if error stopped.

Follow the below methods to troubleshoot – Event ID 1121 issue:

Allow period when replication can run between the sites.

Try the following steps:

  1. Open AD Sites and Services, then expand Sties\ Default-First-Site-Name.
  2. After that – On the right panel, you will see NTDS Site Settings.
  3. Here, right-click on NTDS Site Settings and select properties.
  4. Then click Change Schedule, to see if it was set to none. It is recommended to set to “once per hour”.
  5. After changing the setting, you need to reboot the server.
Another method to get this done: