Juniper router issue

Our network is a little complicated to explain but I will attempt to describe our problem. We currently have a Cisco 1800 for our main router and are attempting to move to a Juniper SRX 220. We can successfully cut over and get out to the internet and remote locations connected back to us but some of our other systems are not working. We have 4 other routers that sit on our network for vendors to route to their individual systems. They are working on the cisco but no on the juniper even though all the routes are in place. Is there another place we need to be looking to help facilitate making these devices work? If I can provide more information let me know what would be helpful.