我的中间件设置：

from w3lib.http import basic_auth_header 
class CustomProxyMiddleware(object):
    def process_request(self, request, spider):
        request.meta['proxy'] = "111.11.11.111:1111"
        request.headers['Proxy - Authorization'] = basic_auth_header('login', 'password')

我的设置：

DOWNLOADER_MIDDLEWARES = {
    'my_project.middlewares.CustomProxyMiddleware': 350,
    'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 400,
}

启动后，我收到一个错误：

scrapy.core.downloader.handlers.http11.TunnelError: Could not open CONNECT tunnel with proxy 217.29.53.106:51725 [{'status': 407, 'reason': b'Proxy Authentication Required'}]

原因是什么，如何修复它？（我使用有效的https代理）