module stop to answer to AT-commands


#1

Hi !
I have test boad with module SIM800C https://www.aliexpress.com/store/product/Free-Shipping-Smallest-SIM800L-GPRS-GSM-Module-MicroSIM-Card-Core-BOard-Quad-band-TTL-Serial-Port/2342338_32708504554.html?spm=2114.12010612.0.0.510bed99qfIC1e
When I connect to module with PC and send AT-commands it work perfect :
ATI = SIM800 R14.18
AT+CGMR = Revision:1418B05SIM800C24_BT
AT+CSQ = 16,0

But after I enter SIM card to connector, module stop to answer to AT-commands and LED stopped to blink.
I checked with other module but it made same.
What to do ?