TypeError in scrapyd

I have started scrapyd in my cmd, and the website "localhost:8600" shows normally. Then I began to deploy a project named scrapyd_prac, and changed the content of project's "scrapy.cfg' as:

 [deploy:localhost]
    url = http://localhost:6800/
    project = scrapyd_prac

Then I execute the command in cmd:

python D:\scrapyd_test\Scripts\scrapyd-deploy localhost -p scrapyd_prac

and it returns like this:

Packing version 1500791181
Deploying to project "scrapyd_prac" in http://localhost:6800/addversion.json
Server response (200):

{"status": "error", "message": "environment can only contain strings",        "node_name": "YLMF-1609111715"}

I am confused, please help me.