In the development process, sometimes if there is a need for WeChat payment and WeChat login, you need to fill in the package name in the signature tool provided by WeChat, and then generate a signature for the application signature filled in when creating the application. However, sometimes you can directly fill in the package name in the following figure and report an error directly below.

The reason for the error is packageName. The package name in AndroidManifest is different from the applicationId in build.gradle in app.

Just make the packageName the same as the applicationId in build.gradle in the application. As long as the package name is written correctly, the corresponding application signature will be generated.