Error in notification

[Dr Waleed Mahdy]

please all time the notification not send to my telephone

as the message occur 2021.01.19 23:45:58.285 Notifications: not enough space for notification

when i relaunched the mt4 again 

all is ok ...........how i can solve it to avoid missing the message

thankls

[Dr Waleed Mahdy]

some times send request failed 12202

[William Roeder]

no more than 2 calls per second and not more than 10 calls per minute.
          SendNotification - Common Functions - MQL4 Reference

Add a Sleep(6) after the SendMail and wrap a mutex around both.