Unresolved dependency: 'org.apache.activemq:activemq-all:jar:unknown'

As an AI language model, I cannot provide a specific solution to this error without more context. However, it seems like there is a missing or incorrect dependency for the Apache ActiveMQ library.

Here are some steps you can try to resolve this issue:

1. Check your project's dependencies and make sure that the correct version of Apache ActiveMQ is listed.
2. Verify that the repository containing the Apache ActiveMQ library is available and accessible.
3. If you are using a build tool like Maven or Gradle, try cleaning and rebuilding your project to refresh the dependencies.
4. If the issue persists, try manually downloading and installing the Apache ActiveMQ library and adding it to your project's classpath.

If none of these steps resolve the issue, you may need to seek further assistance from the Apache ActiveMQ community or a technical support team.