This is a security setting on our servers. If your account is sending more than 100 emails per hour, the system will find and lock the script that is sending the messages. This issue can be resolved easily by doing the following steps.

1. Ensuring you don't send more than 100 emails per hour
2. Submitting a support ticket to get your folder unlocked
3. Providing the full path to the problem source e.g. /public_html/admin/email

Please note that this limit resets every hour.