Did you check the log output? The feeder has indeed a connection to our servers but it doesn't seem to stream any data. This is either the case when the setup is broken and doesn't receive anything (which I assume is not the case) or when the feeder cannot connect to your local dump1090.
Can you check the log messages by running "sudo journalctl -b 0 -u opensky-feeder" if there are any errors?
Here is the output. Can it be a firewall issue?
-- Logs begin at Thu 2016-11-03 17:16:42 UTC, end at Sun 2018-03-11 09:38:47 UTC. --
Mar 08 06:49:57 raspberrypi systemd[1]: Started OpenSky Daemon.
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize STAT
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize POS
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize NET
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize TB
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize SERIAL
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize BUF
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize RELAY
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize RC
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize FILTER
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Initialize RECV
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start STAT
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start POS
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start NET
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start TB
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start SERIAL
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start RELAY
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start RC
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start FILTER
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [COMP] Start RECV
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [NET] Trying to connect to 'collector.opensky-network.org': [194.209.200.4]:10004
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [NET] connected to 'collector.opensky-network.org'
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [LOGIN] Sending Device ID 5, Version 2.1.6
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [LOGIN] Sending Serial Number -1408236984
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [GPS] Sending position +58.4680°, +16.3200°, +65.00m
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [LOGIN] Sending Username 'stehul'
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [TB] Setting sync filter: 0
Mar 08 06:49:57 raspberrypi openskyd-dump1090[693]: [INFO] [TB] Setting ext squitter only filter: 0
Mar 08 06:50:01 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 08 06:50:01 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 08 06:50:05 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 08 06:50:05 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 08 06:50:09 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 08 06:50:09 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 08 06:50:13 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 08 06:50:13 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 08 06:50:17 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 08 06:50:17 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:26 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:26 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:30 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:30 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:34 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:34 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:38 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:38 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:42 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:42 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:46 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:46 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:51 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:51 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:55 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:55 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:26:59 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:26:59 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'
Mar 11 08:27:03 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] Trying to connect to 'localhost': [127.0.0.1]:8754
Mar 11 08:27:03 raspberrypi openskyd-dump1090[693]: [INFO] [INPUT] connected to 'localhost'