Joke Collection Website - Blessing messages - What does it mean that SMS signature is illegal?

What does it mean that SMS signature is illegal?

The content of the representative signature does not comply with the regulations.

The system will automatically detect when signing a text message. If the conditions are not met, it will prompt that the text message signature is illegal.

Prevent illegal information from appearing in signature information. When users set and send signatures, the system will automatically filter illegal words, and signatures that do not meet the conditions will not be allowed to be set and sent. Either because X is not entered, or the content after X is empty, or the content is too long (more than 48 characters).