Trying to login to Pokémon Go with Google and I get a Error 403 code? I set up a Pokémon Go account for my 5 year old on an old iPhone and we've been using a hotspot so he can play. I also made him his own kids email account and Google account. A few days ago the app randomly logged him out and we can't get back into his account.
At first it said that I wasn't allowed to login because I don't have permission since it's a kids account. But now it's just giving me an error message. I'm at a loss, how can we get back in?
There is a Pokemon support article on this:

These error messages may indicate a temporary issue with the servers.
First, close and then reopen the Pokémon GO app:
iPhone X or later: Swipe up from the bottom of the screen and pause in the middle of the screen to view the most recently used apps. Swipe left or right to locate the Pokémon GO app, and then swipe up on the Pokémon GO app to close.
iPhone 8 or earlier: Double-tap the Home button to view the most recently used apps, swipe left or right to locate the Pokémon GO app, and then swipe up on the Pokémon GO app to close.
If that doesn’t resolve the issue, please visit the Niantic support page at https://niantic.helpshift.com/a/pokemon-go/?p=web for more information.
Note: The link takes you to a website that is not created or maintained by The Pokémon Company International.