One important step to setting up a Foundation Hub environment is to set up firewall permissions for each ULM app(s). Without these it can cause certain pieces of Foundation to fail. This primarily occurs when a  ULM application connects another application to use a function or pull data from a different server. 

For example in Compose Capture a user can use the review button to review the results of a recipe. The Review function borrowed from the Hub application. If firewall rules do not allow Compose to access the Hub server then this will fail. 

Due to this it is important to have firewall rules in place that allow applications to communicate with each other. To do this make sure the firewalls are open in both ends for each application registered to each other.

For example the only application that is register is to Hub is Compose Capture. To make sure the cross functionality to be successful both servers need to have the firewall open to both servers. In other words the Compose Capture server needs to be open to the Hub server and the Hub server needs to be open to the Compose Capture server.

Hub Server => Open Firewall => Compose Capture Server

Compose Capture Server => Open Firewall => Hub Server

One last note, this has to be done for each application registered to Hub that is on another server.