+cms error: 536


I am trying to write a message on memory using the CMGW command. Before the function in the program is called it´s possible to run the at+cmgw=“070xxxxx” >testing text “ctrl-Z” and save it to memory but when running it from the program I get “+CMS ERROR: 536” and after that a also get that error when using cmgw from hyperterminal. Below is part of my code.

wm_strcpy(Buff, "AT+CMGW=\"");
wm_strcat(Buff, tel_nr);
wm_strcat(Buff, "\"");
adl_atCmdCreate(Buff,TRUE, (adl_atRspHandler_t) my_sms_response_handler,">",NULL );

s16 my_sms_response_handler(adl_atResponse_t *paras)
	TRACE (( 1, "my_sms_response_handler"));
	adl_atCmdSendText ( ADL_AT_PORT_TYPE ( paras->Dest, ADL_AT_RSP ), "Testing!!!");
	return FALSE;