SIM800 Failed to connect over PPP (AT+CGDATA="PPP",1)

[kopecdav]

Hi,

Iam triing to integrate SIM800C24 into our hardware design. Almost everything works well.

I was able to communicate the device over AT commands, I succesfully connected to a network and initialize a PDP context.
problem comes when i try to connect device over PPP protocol with command AT+CGDATA="PPP",1 (or ATD*99#)
The device respond as "CONNECTED" but imidiatelly after that start to blink fast with the netwrok LED and returns the message "Failed to create the dial"

I have tried to flash a latest firmware, check the power supply and anntena signal and everything seems to be ok, I can easily send SMS (phone call i cant try since is disabled on my SIM card).

does anybody know what is the cause of this issue?
Thank you very much ! and iam adding the sequence of used AT commands and responses

Log from serial terminal

AT

OK
AT+CPIN?
AT+CPIN?

+CPIN: READY

OK
AT+CREG=2
AT+CREG=2

OK
AT+CGREG=2
AT+CGREG=2

OK
AT+CGDCONT=1,"IP","TM"
AT+CGDCONT=1,"IP","TM"

OK
AT+CGATT?
AT+CGATT?

+CGATT: 1

OK
AT+CSQ?
AT+CSQ?

ERROR
AT+CSQ
AT+CSQ

+CSQ: 20,0

OK
AT+CGDATA="PPP",1
AT+CGDATA="PPP",1

CONNECT
[00][00][00][00][00][00]RichEd32.dll[00]Failed to create the dia[00][00][00][00][00][00]RichEd32.dll[00]Failed to create the dia