Why does the domain name's sending volume reach the upper limit on the same day?

Each domain name has a certain credit limit every day, and the system will dynamically adjust it according to the sending and receiving conditions of the domain name.
Note (Standard and Professional Edition Email Sending: 1,000 emails per user per day. After exceeding the limit, 1 email can be sent every 10 minutes).
When you encounter the notification that the sending volume has reached the upper limit, the possible reasons and corresponding measures are as follows:
1. The sending volume has reached the upper limit of the day. It is recommended that you send it again the next day.
2. Member accounts were hacked, and a large number of spam emails were sent, which took up the volume of domain names. In this case, it is recommended that you contact the administrator of the domain name to check whether there is an abnormal account, and take necessary measures.