nrf9160 Socket error: POLLHUP

on connection, the modem gets reset after ~ 1 minute from activation:


[00:00:00.421,386] <dbg> nrf_cloud_transport.nct_topics_populate: shadow_get_topic: $aws/things/nrf-352656100222853/shadow/get
Connecting to LTE network. This may take several minutes.
[00:00:00.438,995] <dbg> lte_lc.w_lte_lc_connect: Network mode: AT%XSYSTEMMODE=1,0,0,1
[00:00:02.776,672] <dbg> lte_lc.at_handler: recv: +CEREG: 2,"035D","00378620",7,0,0,"11100000","11100000"

[00:00:03.656,738] <dbg> lte_lc.at_handler: recv: +CEREG: 1,"035D","00378620",7,,,"11100000","11100000"

Connected to LTE network
[00:00:03.842,681] <dbg> nrf_cloud_transport.nct_connect: IPv4 Address 0x5f7ee722
Socket error: POLLHUP
LTE link disconnect
Shutdown modem
***** Booting Zephyr OS build v1.14.99-ncs3-snapshot2-2074-ga2c36f15843f *****

I erased the device from NRF cloud, but this issue still occure, please advice.

happen on two devices, I use the same SIM card for both devices