Jeff01
You may want to "lock" the ip address of your AIO in your router. (If you don't then the address used by the AIO may change, and the local app access will then need to be reset.)
How you fix the ip address depends on what router you are using, but a search on google should sort you out.
BTW, you should also make sure that your installer has locked down the wifi on both your AIO and Gateway. They should have done, but sometimes it gets forgotten - it was for me. Go and stand near your AIO and your Gateway with a phone, and see if it can see any new wifi networks (mine were called WJxxxxxxx and WKxxxxxx respectively IIRC). If you can see if you can connect to them and get internet access. If you can then they have been left open for all comers to use. Post back here and someone will tell you how to secure them