Traceback (most recent call last):
  File "/usr/lib64/python3.6/site-packages/twisted/internet/defer.py", line 1418, in _inlineCallbacks
    result = g.send(result)
  File "/usr/lib/python3.6/site-packages/scrapy/core/downloader/middleware.py", line 38, in process_request
    response = yield method(request=request, spider=spider)
  File "/usr/lib/python3.6/site-packages/scrapy_proxies/randomproxy.py", line 111, in process_request
    raise ValueError('All proxies are unusable, cannot proceed')
ValueError: All proxies are unusable, cannot proceed