Snapshots created manually outside of the replication schedule will often block subsequent scheduled replication tasks.
Scheduled replication tasks look for a specific naming convention with a "GMT" time stamp but manual replication tasks can use custom names which will supersede the scheduled snapshots.
To correct this issue and allow replication task to begin running you will need to remove the manually created replication snapshots and checkpoints which will allow the scheduled replication to resume.
As a general practice we recommend sticking to scheduled replication tasks, and only manually trigger replication where needed during troubleshooting.
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