Your Email Provider may restrict the amount of time between checking for New Messages to a minimum of 15 minutes (or 720 seconds). This means checking more often will bring up an Error Message.
This Error may appear as any of the following:
Hotmail Login Allowed Every 15 Minutes
Login allowed every 720 seconds
ERR Exceeded the login limit for a 15 minute period. Reduce the frequency of requests to the POP3 server.
Since this limit is set by your provider and cannot be changed, you will need to adjust your IncrediMail settings:
Open IncrediMail, click the 'Tools' menu (marked in red) and then 'Options' (marked in blue).
Under the 'General' tab (marked in red below), in the section of 'Check for new messages every ___ minutes', change the time to 15 minutes (as marked in blue).
This will correct the amount of time between automatic retrieval of your messages. If you attempt to receive messages manually in a shorter amount of time, you will continue to receive the Error Message.