Mails sent to internal Users are counted into the daily email limit
|Knowledge Article Number||000212698|
|Description||Customer was using setTargetObjectID() to send the email and encountered SINGLE_EMAIL_LIMIT_EXCEEDED error.|
|Resolution||According to the documentation on setTargetObjectID() , all email must have a recipient value of at least one of the following:
Here the targeObjectIds allows you to send an email to UserID1.it uses the standard email field on that user to then send the email however if you write:
ccAddresses=user.Email (where 0 is UserID1)
In this scenario, you will be sending 2 emails to the same user instead of one and will consume 1 of the email limit because you just passed a plain text email into the ccAddresses.
Please note specifying UserID1 does not mean you can go and use the plain text email of said user in any email in that method and it not count towards the limit.