Update ,
Well after trying to find a way to contact Defi . I finally did through Facebook !
They were really helpful to explain . I was very great full that they took the time to write a great long reply . Now it works flawless . This is what they sent . I know it's a Defi and a lot probably won't get it due to its expense . But it's a good to know and may help with other devices when connecting to an OBD blu tooth system.

Defi
Thank you for using our product.
The app and the adapter need to be connected via bluetooth after the iPhone and the adapter are connected via bluetooth.
After turning on the car engine, it takes 10 seconds to start the adapter. Then it takes a few seconds to connect the adapter and an iPhone via bluetooth. And then the app needs to be connected to the adapter via bluetooth.
It can be confirmed if the iPhone is connected to the adapter via bluetooth in the settings > Bluetooth > MY DEVICES.
We would like you to try to connect the app to the adapter after confirming your iPhone is connected to the adapter.
1)Car endine starts
10 seconds
2)Adapter starts
a few seconds
3)iPhone connects to adapter
then
4)App connects to adapter (MENU > Communication)
Sorry for the complex procedure. We hope it works!