What Phantom do you have and are you on the latest updates?
Also, do you have enable device debugging on. If not, there's instructions on Google on how to do it.
Your on 2.4.3 now since yesterday right?
it seems to be something within the app and your phone. Can you try another device and see if that works.
I'll copy this and post it on the other thread you responded to.
I think I have found the source of the issue. It seems to be a bug in the Android app version.
Samsung SGS5 Android 5.0 - can not set the expo
Samsung SGS7 Android 5.1.1 - can not set the expo
Nexus Asus 7“ Android 6.0.1 - can not set the expo
iPhone 5S – works
iPhone 6 - works
I think I have found the source of the issue. It seems to be a bug in the Android app version.
Instead of sliding to change values, manually type the value with a decimal point. There is comma in the value and hence the DJI go app cannot validate. If you cannot type the value, start a typing app on your phone and enter 0.20 (your value) and copy as paste it. ALL 3 values MUST be a valid number before it can write the changes.
When you use the curve to change the number, than it generated number without decimal point (i.e. 030) which is out of range. If you want to rdit the number in the cell bellow the curve then the comma "," is expected, but you can type only dot ".". It is usual bug in Android app as I figured out already.