cannot connect to AWS IoT Core

[chaweewatp]

Here is error

Rebooting ...OK
Check module status ...OK
Setup ...OK
IMSI : 520039400067967
ICCID : 8966031940014321255
IMEI : 868333030875039
FW ver : 1752B13SIM7020E
Signal : -81 dBm
Connecting OK
APN : DEVKIT.NB
---------- Connected ----------
Certificate Setup. Please wait 1-2 minutes
Please check your server/port/Certificates again.

cannot connectMQTT

MQTT connected

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Topic : esp32/sub

Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.

Core 1 register dump:
PC : 0x400d8adc PS : 0x00060e30 A0 : 0x800d8ad4 A1 : 0x3ffb2670
A2 : 0x00000003 A3 : 0x3ffc1bc8 A4 : 0x00000003 A5 : 0x0000ff00
A6 : 0x00ff0000 A7 : 0xff000000 A8 : 0x800d9b3a A9 : 0x3ffb2690
A10 : 0x00000002 A11 : 0x00000000 A12 : 0x0000000a A13 : 0x0000ff00
A14 : 0x00ff0000 A15 : 0xff000000 SAR : 0x0000001b EXCCAUSE: 0x0000001c
EXCVADDR: 0x00000087 LBEG : 0x40086215 LEND : 0x40086225 LCOUNT : 0xffffffff

Backtrace:0x400d8ad9:0x3ffb26700x400d8ad1:0x3ffb26d0 0x400d659b:0x3ffb26f0 0x400d17c2:0x3ffb2730 0x400d1aa3:0x3ffb27c0 0x400daf76:0x3ffb2820

ELF file SHA256: 0000000000000000

Rebooting...
ets Jun 8 2016 00:22:57

rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0030,len:1184
load:0x40078000,len:13132
load:0x40080400,len:3036
entry 0x400805e4