Receiver is online but not sending any data (no aircraft in coverage or problem with antenna) - have found out this error today. Used to work just fine.

I reconfigured the settings and updated the system but no luck so far. I'm using DVT-B USB stick (WINGONEER Digitale USB 2.0 DVB-T SDR+DAB+FM RTL2832U+R820T2).

Checking the status:
Code:
● fr24feed.service - Flightradar24 Decoder & Feeder
   Loaded: loaded (/etc/systemd/system/fr24feed.service; enabled; vendor preset: enabled)
   Active: active (running) since Sun 2019-01-06 20:03:30 UTC; 2min 40s ago
  Process: 276 ExecStartPre=/usr/lib/fr24/create_missing_directories.sh (code=exited, status=0/SUCCESS)
  Process: 264 ExecStartPre=/usr/lib/fr24/unregister_kernel_modules.sh (code=exited, status=0/SUCCESS)
  Process: 223 ExecStartPre=/usr/lib/fr24/install_dump1090.sh (code=exited, status=0/SUCCESS)
 Main PID: 289 (fr24feed)
   CGroup: /system.slice/fr24feed.service
           └─289 /usr/bin/fr24feed

Jan 06 20:03:28 radar systemd[1]: Starting Flightradar24 Decoder & Feeder...
Jan 06 20:03:30 radar systemd[1]: Started Flightradar24 Decoder & Feeder.
Running the sudo fr24feeed:
Code:
2019-01-06 20:12:07 | [main][i]FR24 Feeder/Decoder
2019-01-06 20:12:07 | [main][i]Version: 1.0.23-8/generic
2019-01-06 20:12:07 | [main][i]Built on Oct 16 2018 08:10:47 (HEAD-2d57e58.git/Linux/static_armel)
2019-01-06 20:12:07 | [main][i]Running on: raspbian9
2019-01-06 20:12:07 | [main][i]Local IP(s): 192.168.123.235
2019-01-06 20:12:07 | [main][i]Copyright 2012-2018 Flightradar24 AB
2019-01-06 20:12:07 | [main][i]DNS mode: PING
2019-01-06 20:12:07 | [main][i]Automatic updates are ENABLED
2019-01-06 20:12:07 | ERROR: rmmod: ERROR: Module dvb_usb_rtl28xxu is not currently loaded
2019-01-06 20:12:07 | [main][i]Reader thread started
2019-01-06 20:12:07 | [time][i]Synchronizing time via NTP
2019-01-06 20:12:07 | [reader][i]Initializing reader
2019-01-06 20:12:07 | [master][i]Starting processing thread
2019-01-06 20:12:07 | [reader][i]Connecting to DVBT receiver via (exe:///usr/bin/dump1090-mutability  --raw)
2019-01-06 20:12:07 | [[httpd][e]bind function failed, errno: 98
2019-01-06 20:12:07 | reader][i]Connected to the receiver, configuring
2019-01-06 20:12:07 | [httpd][d]Master thread terminated
2019-01-06 20:12:07 | [reader][i]Configured, processing messages
Sun Jan  6 20:12:07 2019 UTC  dump1090-mutability v1.14 starting up.
Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001 (currently selected)
usb_claim_interface error -6
Error opening the RTLSDR device: Device or resource busy
2019-01-06 20:12:07 | [reader][i]Connection terminated
2019-01-06 20:12:07 | [main][i]Terminating child process 1744 with SIGTERM
Tried to google:
ERROR: rmmod: ERROR: Module dvb_usb_rtl28xxu is not currently loaded - found sth with blacklisting but did not work
usb_claim_interface error -6 - didn't anything with -6