PDU Session success,but N3 interface is not ok (test "echo request but no response")

PDUSessionSuccess.pcap (27.1 KB) 0113UPDlog.docx (21.6 KB)
With many helps from the forum ,We have the right procedure with commercial RAN, but we test from the RAN, N3 seems link failure. We test GTPU request (echo request) but with no response. Is there any experience to share ? Thanks !

ping is ok from each other