There are many possible reasons for "token verification failed". Other netizens have almost exhausted them, but I haven't seen what I encountered on the Internet, so I will record it here.
The reason for the failure was a coding problem;
Since I was developing in a project, I checked in order from business logic to technical logic, to domain name, filing, network, and coding.
Later I found that there is such a code include(../data.config.php) at the project entrance. In front of this code, echo $_GET['echostr'] can pass, but after this code, echo $_GET['echostr'], it fails.
The original encoding format of the data.config.php file is (open in notepad++)
Adjust the format to 
The problem is solved.
In fact, utf-8 essentially has no difference between BOM and non-BOM. There will definitely be no misunderstanding during transmission, but there is nothing you can do about having two formats. I will explain in detail what a BOM is in another article.
Here is a hexadecimal comparison of different encodings.
