I just finished a chat with Arlo support and they acknowledged that the phone permissions/mode setting issue is a bug that they still have to address. Until they do, they suggested using another platform for updates (PC version works) or reverting the Android app to the last October version (which works for me on my Samsung S9).
Had the same issue.
It appears that Arlo authentication cant handle a disconnect and reconnect immediately. If I had to guess probably a caching issue.
Wait 24 hours and try again.
Solved the issue for me
A couple of days ago, I turned off notifications for Arlo on my LG Android and it is now allowing me to Arm and Disarm the cameras. It wasn't working before and caused me to use the website to change it. They must have fixed something. However I still occasionally get the error message that shuts down the Arlo app. It never shows the reason and most of the time does it when I don't even have the app active.
Many of the app crash issues being discussed here should now be resolved with the release of the 2.6.4 version of the Android mobile app.
Please make sure you have the latest version downloaded and installed: Arlo Android App - 2.6.4 - 27th November 2018
We're continuing to investigate reports of other issues.
UPDATE: I'm not sure what happened, but, he just uninstalled the app and reinstalled. As soon as he reinstalled he was told to "Update". He clicked the "Update" button as indicated and everything is good now? He was never offered the "Update" option before, it would just say "Arlo has stopped". I see that the update was dated 11/27/2018.
I wish I knew how to help others in this situation, but, I'm certainly happy his Arlo app is now working properly.