Email settings OAuth

[Fuksbet]

Hello
What should I do to prevent e-mails from being sent to SPAM in the newly created www.fuksbet.com forum?

Tries to add and verify Google OAuth options
I set up an Administrator@fuksbet.com account on gmail (domain verified)


I click



And every time an authorization error pops up




Any ideas to solve this problem?
However, please explain as if to a child