In addition to other external accounts, I have configured my Hotmail via POP in Gmail as an external account. Today, I was organizing all those old emails from Hotmail in my gmail account – deleting, reading, marked as read etc. After a while, I was kicked out of Gmail and when i tried to relogin, I got the below error message.
Account Lockdown: Unusual Activity Detected
This account has been locked down due to unusual account activity. It may take up to 24 hours for you to regain access.
Read more about this issue in Gmail help page.
Reason : This could have happened as I did a lot of deletions, downloading many emails from hotmail account including spam. This also happens when you try to very quickly read the emails.
So, it better to use external accounts with IMAP access which would keep all our emails, spam stored in external mail acct.
Quick Fix: Just exit and close all your browsers, clear the cookies and restart your browser or maybe the system too. This should help in most cases.