The subscription have been marked inactive and must be reinitialized into a replication

Hi Team

I keep on getting the following error on Transnational Replication setup in SQL 2005.

below is the error message:

The subscription(s) have been marked inactive and must be reinitialized. NoSync subscriptions will need to be dropped and recreated. 

note: myTransnational  replication working fine, but I see the sql server error log getting above error message how we can fix this issue.