Thank you for your post.
Has anything else changed on your system besides the router firmware? Are you able to access other applications via 3G? FileMaker Pro uses port 5003 to share files over the network, so make sure port 5003 is open. Have you rebooted the router?
Do you have other FileMaker Pro clients able to access the database files (not via 3g)?
Any additional information may be helpful in narrowing down the possible causes.
Has anything else changed on your system besides the router firmware?
Not that I can tell.
Are you able to access other applications via 3G?
This is the only program that I access via 3G.
FileMaker Pro uses port 5003 to share files over the network, so make sure port 5003 is open. Have you rebooted the router?
Port 5003 is open, I can access the database over my home wifi network, and I have rebooted the router, and the cable modem.
In the favorite hosts section on Filemaker Go, I put in the router's IP address correct?
Has the router's IP address been changed on you? Unless you have arranged with your ISP (internet service provider) for a static IP address, this address can change from time to time.
Also check with your ISP to make sure they are not blocking access. Some posters here have reported that their ISP was blocking access.
I finally took my iMac, Airport Extreme, and iPad to the Apple store. The people at the genuis bar were most helpful. I had everything set up right as far as the port forwarding goes, but in the "Settings" "Network", under "DNS", I had to set my DNS server to the routers internal ip address. After this, I then had to delete the database from the "Recent Files" section in Filemaker Go, then reattach it. Everything now works fine. By the way, I am now running Filemaker Go on an iPad 3 with 4G LTE, WOW, what a differance. My pop up menus now scroll in real time.