I am having the same problem with my "Moto G power" phone. Everything works fine on my older Samsung Galaxy Tab 8, but ever since the android version on my phone was updated, I cant get chart updates. I tried factory resetting my phone yesterday, and the first download worked, but when I went back to add more area I got the message that it couldnt connect to the server. I filed a bug report back in June, but closed it after I rebooted the phone and it worked to download more charts. The next time i tried to update, I ended up with the same error.
I think one of the new android file permission settings is getting in the way, vs. communication with the server. This is in my ifly log, and I attached a screen shot with the error message that pops up:
[Info] [00.533 sec]Adding Unique Mount: True, '/storage/FCA0-AA4B/Android/data/iFly.GPS/files/' [SDCard, 49462 MB,<REMOVABLE>]
[Info] [00.536 sec]Finding External SD Card Path...
[Error] [00.580 sec]DiskMountManager._FindExternalSDCards() failed: System.UnauthorizedAccessException: Access to the path '/storage' is denied. ---> System.IO.IOException: Permission denied