Issue Description: An error occurs that prevents signing in to Pokémon HOME from Pokémon GO.

Issue Status: Investigating. In the meantime, please try the troubleshooting steps below. Please note that the troubleshooting steps may or may not solve the issue.

Troubleshooting Steps:
Sign out from https://accounts.nintendo.com/portal on all applicable devices, including Nintendo Switch, mobile device (all browsers), and personal computer.
Uninstall Pokémon GO and Pokémon HOME on your mobile device.
Reinstall both apps on your mobile device.
Open Pokémon HOME and log into your Nintendo account: Pokémon GO > Log into your account > Main Menu > Settings > Connected Devices and Services > Pokémon HOME > “Sign in with Nintendo”.