The reasons that led to the "GMail account lock down" can be so many that one wonders how most of the GMail accounts are still working:
Thanks for your report. We apologize for any confusion or inconvenience. For your security, we may temporarily disable access to your account if our system detects abnormal usage. It will take between one minute and 24 hours for you to regain access, depending on the behaviour our system detected. Abnormal usage includes, but is not limited to:
- Receiving, deleting, or popping out large amounts of mail (via POP) in a short period of time
- Sending a large number of undeliverable messages (messages that bounce back)
- Using third party file-sharing or storing software, or software that automatically logs in to your account and that is not supported by GMail
- Multiple instances of your mail account opened
- Browser-related issues. Please note that if you find your browser continually reloading while attempting to access your inbox, it is likely a browser issue, and it may be necessary to clear your browser's cache and cookies.
If you feel that access should not have been disabled, please visit http://mail.google.com/support/bin/answer.py?answer=53897 for troubleshooting tips. Sincerely, The Google Team
