worker_process get stuck when process CoolProxyProvider

[chess99]

Describe the bug
worker_process get stuck when process CoolProxyProvider

To Reproduce

run with docker
docker run -d -p 8899:8899 -p 8081:8081 -v /var/www/scylla:/var/www/scylla --name scylla wildcat/scylla:latest

log info as follow:

08:29:45 DEBUG: Get a provider from the provider queue: A2uProvider
...
08:29:46 DEBUG: Get a provider from the provider queue: CoolProxyProvider
08:29:47 DEBUG: Catch requests.RequestException for proxy ip: 151.106.10.103
08:29:47 DEBUG: HTTPConnectionPool(host='151.106.10.103', port=8080): Max retries exceeded with url: http://api.ipify.org/?format=json (Caused by ProxyError('Cannot connect to proxy.', NewConn    ectionError('<urllib3.connection.HTTPConnection object at 0x7f2d6469c860>: Failed to establish a new connection: [Errno 111] Connection refused',)))
08:29:57 DEBUG: starting render js...

then there is no other provider appears, also there is no "end render js..." printed
only repeat these:

08:59:47 DEBUG: feed 8 providers...
08:59:47 DEBUG: Feed 18 proxies from the database for a second time validation
...

Additional context
IMAGE ID: 7acd88dbc24c