Recently I wrote about alternative way to export/import notebooks in pthon https://community.databricks.com/s/question/0D53f00001TgT52CAF/import-notebook-with-python-script-us... This way you will get more readable error/message (often it is related to host name or access rights).

    pip install databricks-cli

    from databricks_cli.workspace.api import WorkspaceApi
    from databricks_cli.sdk.api_client import ApiClient
     
    client = ApiClient(
        host='https://your.databricks-url.net',
        token=api_key
    )
    workspace_api = WorkspaceApi(client)
    workspace_api.import_workspace(
        source_path="/your/dir/here/hello.py",
        target_path="/Repos/test/hello.py",
        overwrite=True
    )