There may be multiple cases for this issue. To come for proper conclusion, please verify the jobs correspoding to this replication setup and make sure that they are running..not hung.
If job doesnt seem to be running, try to stop it and rerun, sometimes it will solve the issue
If ur organization allows for REINITIALIZATION of replication, give a try.
If any of the above methods does not work out then, please post the error in the job related to this replication.
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