(Error) Not enough space for notification!

 
(Error) Not enough space for notification!

Please what does it mean and how can I solve it permanently? Sometimes it occurred even when I have few charts open and just one or two orders to notify about.
 

IIRC, the maximum limit on emails, is just like SendNotification: “no more than 2 calls per second and not more than 10 calls per minute.” Add a Sleep(6) after the Send… and wrap a mutex around both (for multiple symbols).