My situation as below:
We are setting up a new domain for a branch office and we started by creating DC1 in the main office and DC2 in another branch office. We then start to build DC3 and DC4 with ifm media install method in the new branch office and moved the 3 domain's fsmo to DC3. As for some reason, we need to change the IP address of DC3 and DC4 using a differnet subnet range, and since then the replication stops replicating newly created objects on DC3 to other DCs.
I checked the repadmin /showrepl command and it shows the replication completed successfully.