Why is SMS blacklisted?

When short messages are blacklisted, the number of short messages sent exceeds the limit. The restrictions for sending short messages are as follows:

1, and the total number of short messages shall not exceed 500/day; .

2. Send no more than 10 short messages containing keywords/day;

3. Send no more than 200 short messages of the same length every day;

4. Send no more than 150 short messages per hour;

5. The maximum number of messages sent on national statutory holidays shall not exceed 2000/day;

6. Conditions for China Mobile and China Unicom to blacklist telecom mobile phone users:

(1) The upper limit of mobile communication is 50 mobile lines per hour; (2) Unicom 280/ hour; (3) After the telecom mobile phone number is blacklisted by China Mobile and China Unicom, the system will automatically cancel it after 48 hours.