Using your Gmail account from multiple locations or devices.Receiving, downloading, or deleting large amounts of mail via POP or IMAP within a short span of time.Sending a large number of emails that go undelivered.This block may last from a minute to 24 hours, or even 30 to 40 hours depending on the type of activity detected by the system. There are some specific activities listed in Google Help Support that may result in blocked access to the service. It may even suspend your account temporarily to protect it from abuse or fraud. If there’s any unusual or suspicious activity on your Google account, it’ll lock you out so you can’t access any of its services. Google takes very strict measures to ensure that its products and services operate according to its security policies. Thankfully, Google allows you to recover your account information, but you’ll need some information like your email address, phone number, or the date you created your account. All these issues could lead to massive losses that would take time to recover from, especially since Google won’t let you back into your account for a certain number of days due to its security holds.