The error message suggests that the jar file located at abfss:/jars/ojdbc8.jar has an invalid authority. This could be due to a number of reasons such as incorrect file path, insufficient permissions, or network restrictions.

Here are a few steps you can take to troubleshoot this issue:

1. Verify the location of the ojdbc8.jar file: Ensure that the jar file is located at the specified path (abfss:/jars/ojdbc8.jar) and that the path is correctly written in your code.

2. Check permissions: Make sure that the Databricks cluster has the necessary permissions to access and install the jar file from the specified location.

3. Network restrictions: There could be network restrictions or firewall settings that are preventing the Databricks cluster from accessing the jar file. You might need to work with your network or security team to check if there are any network restrictions that need to be updated.

4. Oracle database logs: Check the Oracle database logs to see if there are any errors or warnings that may indicate why the connection is failing. You can also check the database performance metrics to see if the database is overloaded or running out of resources.