I cant decode aprs

[joanpao]

Hi,
I am trying to receive APRS with a Raspberry Pi using an RTL-SDR and the command:
rtl_fm -d 0 -f 433.500M -s 24000 -g 20 | direwolf -c /home/pi-star/igate_upv.conf -r 24000 -D 1 -a 10
I do see a frame every 30 seconds, but nothing is being sent to APRS-ISand nothing appears on aprs.fi.
Any suggestions?
Thanks
Juanpa Sánchez
Ea5jtt