Failed to read artifact descriptor for io.springfox:springfox-swagger2:jar:${swagger.version}

This error occurs when Maven is unable to read the artifact descriptor for the specified dependency. The ${swagger.version} variable seems to be undefined or not properly set in the Maven POM file.

To fix this issue, you need to make sure that the variable is defined and has a valid value in your POM file. You can define it in the properties section of your POM file as follows:

<properties>
   <swagger.version>2.9.2</swagger.version>
</properties>

Alternatively, you can replace the ${swagger.version} variable with the actual version number in the dependency declaration as follows:

<dependency>
   <groupId>io.springfox</groupId>
   <artifactId>springfox-swagger2</artifactId>
   <version>2.9.2</version>
</dependency>

After making these changes, run the Maven build again and the error should be resolved.