Reason for the block : Mail rate exceeded limit

Reason for the block : Mail rate exceeded limit

I have not sent many e-mails today, probably around 6. I've just tried to send another and received this message:


"We regret to inform you that your email outgoing has been blocked and you will not be able to send further emails.This was done in accordance with the Zoho Mail  Usage policy .

Reason for the block :  Mail rate exceeded limit

However, we realize that this might have been unintentional. To unblock, please  click here ."

When will my e-mail be unblocked and what is the cause of this?