Login Throttling is necessary to protect your accounts from repeatedly and unsuccessfully is trying to log in (brute-force attack).
This feature restricts the number of guesses an attacker can attempt while giving users multiple opportunities to remember their passwords. It works according to the following scheme:
After 5 unsuccessful retries to log in with the same login / same source IP, you will have a delay before trying again.
Two scenarios are possible:
IMPORTANT: Throttling does not affect the possibility to sign In with Google. It is always available!