During a resynchronization operation, the rate at which a replication pair generates the protection files might decrease or replication might stop completely after you have remapped a source or target LUN.
The source LUN cannot be read and due to that resync files are not reaching to appliance.
You might have received the error after unmapping the source LUN.
Target is not able to apply the differentials/resync files.
Resynchronization operation is not progressing: RPO is increasing.
The number of replication files during differential synchronization is increasing.
No communication from the source LUN to the Oracle MaxRep Replication Engine exists because the differential throttle delay and resynchronization is not progressing.
Map the source LUN to the Replication Engine.
Map the target LUN to the Replication Engine.