Are they low level? In the starter zones, all the quests are autoaccepted which makes it look like Jamba isn't accepting them. Jamba is loaded and active for each toon?

Toon Select and Decline Quest with Team is selected under Jamba > Quest > Quest and pushed to the whole team?

Have you set a Team Channel under Jamba > Advanced > Core:Communications? Make sure your master is set to the same on everyone before pushing the changes, then log out and in again on everyone.