When I start my Uno WiFi as an access point and connect my mobile phone to it, it does a http 'get ' request to it.
What exactly is my mobile phone expecting to get back from the access point?
are you using any blocks?
are you using the wifi extension and its ConnectSSID method (which works for Android < 10)?
https://puravidaapps.com/wifi.php
It would really help if you provided a screenshot of your relevant blocks, so we can see what you are trying to do, and where the problem may be.
To get an image of your blocks, right click in the Blocks Editor and select "Download Blocks as Image". You might want to use an image editor to crop etc. if required. Then post it here in the community.
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.
The blocks in my android app are not really of much relevance. This is more a question about the protocol around an android phone and an access point when a connection is made. I can see the http GET request in Arduino Serial Monitor when I connect to the Arduino access point from the wifi settings in my android phone. At that point I have not even opened up my MIT app inventor app.
sorry, I can't help you with this
and it looks like that question is out of scope for this community...
Taifun