Replication monitor reports that publisher is ok, distributor is ok, subcribers are ok! Yet I make or update the publisher database, yet couldn't see the update reflected on the subscribers!

Hello Pros,

I enabled or created replication using the 'text book rules'. My replication monitor reports that publisher is OK, distributor is OK, subscribers are OK! Yet, when I make or update the publisher database, I couldn't see the update reflected on the subscribers!How do I solve this please?

Also, one message from one of the agents states "NO REPLICATED DATA AVAILABLE"

I've also observed that replication on some of my database only takes effect on tables (I'm limiting my service delivery to replicating only tables) with a PRIMARY KEY CONSTRAINT (at least from my observation). Please why is that so. Will appreciate responses.

Thank you.