Thank you for your post, and I apologize for the late reply.
Without seeing your database file, it is difficult to determine why the portal information is not showing up in FileMaker Go.
In case FileMaker Go has a memory issue, try rebooting FileMaker Go. If the iPhone is having a memory issue, try rebooting the iPhone. In case the layout is damaged, try creating a new layout (do not duplicate) with just the portal.
I know it has been a couple of weeks, so if you have found a resolution, please post here so others with the same symptoms can benefit.