Is this Lean issue

The error message you're seeing is a fatal unhandled exception when running the QuantConnect.Lean.Launcher.dll with the dotnet command. This could be due to a variety of reasons, such as incorrect configuration settings, missing data, or issues with the Lean engine itself.

One of the common issues that can cause this error is incorrect configuration in the config.json file. For example, in the forum discussion, a user had issues with the debugger refusing to attach because the necessary changes were not made to the local version of config.json.

Here is an example of how the config.json file should look like for Python:

{
"environment": "backtesting",
"algorithm-type-name": "BasicTemplateFrameworkAlgorithm",
"algorithm-language": "Python",
"algorithm-location": "../../../Algorithm.Python/BasicTemplateFrameworkAlgorithm.py",
"data-folder": "../../../Data/",
"debugging": true,
"debugging-method": "PTVSD",
"log-handler": "QuantConnect.Logging.CompositeLogHandler",
"messaging-handler": "QuantConnect.Messaging.Messaging",
"job-queue-handler": "QuantConnect.Queues.JobQueue",
"api-handler": "QuantConnect.Api.Api",
}

Please ensure that your config.json file is correctly set up, especially the algorithm-location and data-folder fields.

If the issue persists, it could be due to a bug in the Lean engine. In such a case, you might want to report the issue on the QuantConnect's Lean GitHub page.