What protocol is SMS interface?

First of all, CMPP2.0 is a short message gateway interface protocol for operators.

Secondly, even if you send a short message through the interface of this protocol, it may not be directly received by users, because the short message you send through this protocol is first sent to the operator's gateway platform (which should be made by Huawei in most areas at present), and then the gateway platform routes it to each business processing sub-module of the operator for processing according to various rules, and then the short message is sent to the gateway platform after being processed by each business module, and then sent to users by the gateway platform.

Finally, either the gateway platform didn't receive your message, or they didn't handle it for some reason, which may also be related to the business logic within the operator. There are many reasons for the failure, and you can't send short messages to users just because you adjust an interface.

For example, here, I don't know which SMS interface service you are using. Does this service support China Mobile?

I hope it helps you.