I have a similar issue: upon re-boot the Adguard won't load - but no error message, no icon in the menu bar - just isn't loading at all.
I can manually start Adguard with no issues whatsoever.
OK, all is OK now:
first of all as long as I had free trial active there was no way to login / logout (I downloaded the app from AppStore and activated the free trial)
once the trial ended my premium version reverted to "regular" and LOGIN was possible
I purchased 3-seat license from ADG web...
The tutorial does not match what I can see in the AdGuard app for ios. There is no login option etc therefore there's no way to activate a licence purchased outside of App Store:
I'd like to purchase the 3 device licence currently on sale, through www, but I cannot see any option to activate such a licence on my iPhone. See the screen shot. No option to login etc. None of the options are clickable.
So how the hack am I suppose to activate the licence bought...