If you are attempting to send an email or emails and are receive an error message such as those below;

• An error occurred while sending mail. The mail server responded: too many recipients.
• Delivery has failed=to these recipients or groups:  email@null.null A problem occurred during=the delivery of this message. Please try to resend the message later.

Your email account may have exceeded the number of allowed recipients per email, daily or other email limits. For more information on this, please read more information here: Email Sending Limits