Unknown UE by S_TMSI [G:1 C:1 S_TMSI: oxa5d8383b] Error When Free5GC connecting to Amari Call Pro and Samsung A90

Hi Everyone,
We run into an Unknown UE by S_TMSI error when trying to connected UE, eNb to stage 1Free5GC. We are using Amari CallPro as the eNB. It also has an internal EPC. UE is able to connect to internal EPC and internet with no problem. When we route to connect enB to Free5GC, we are able to see that eNB is connected to Free5GC, as shown in the attached picture .jpg. But we saw the error of UE registration. We have registeredthe test sim card information on the web portal. We leave the APN session as default in the web portal. May I ask is some settings we missed that generate this error?
The pcap file is also attached.

Thank you so much,
Best Regards,

pre07146am2020.pcapng (931.7 KB) enb_free5gc.zip (2.4 MB)