SIP packages not reaching asterisk

I am experiencing this wierd situation.

On my asterisk server listening on port 5060 i run this command

And it confirms that i am receiving SIP packages.

07:16:42.620689 IP (tos 0xc0, ttl 63, id 28895, offset 0, flags [+], proto UDP (17), length 1500) 172.18.21.6.5060 > 172.18.21.229.5060: SIP, length: 1472 INVITE tel:4045;phone-context=+591 SIP/2.0 Content-Length:725 From:<tel:+59165876683>;tag=didb32Y920hZ9e4A ...

on another terminal, but on the same server i have my asterisk -r running with sip set debug on.
however i cannot see any sip packages in my asterisk interface.

I am using asterisk 13.3.2

netstat -lnptu | grep asterisk tcp 0 0 0.0.0.0:5060 0.0.0.0:* LISTEN 2815/asterisk udp 0 0 0.0.0.0:5060 0.0.0.0:* 2815/asterisk

any hints will be really appreciated!