TX and RX does not communicate

I am using MSP430rf2500 for acquiring three sensor signals

below is the  End Point program. it works well. here the reference is VCC with respect to Rss

ADC10CTL1 = INCH_0 + ADC10DIV_2; //set ADC to A0 with clock divide of 2, we might not need the clock divide
ADC10CTL0 = SREF_0 + ADC10SHT_3 + ADC10ON + ADC10IE; //using Vcc and gnd for reference, 16 clks/sample, turn ADC on and enable interrupts
for( int a = 100; a > 0; a-- ); // delay to allow reference to settle, might not be necessary
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
__bis_SR_register(CPUOFF + GIE); // LPM0 with interrupts enabled, this means that it enters low power until ADC conversion is done
results[0] = ADC10MEM; //copy ADC results to x data
ADC10CTL0 &= ~ENC; //reset encode bit
//read y: y is A1 which is P2.1
ADC10CTL1 = INCH_1 + ADC10DIV_2; //set ADC to A1 with clock divide of 2, we might not need the clock divide
ADC10CTL0 = SREF_0 + ADC10SHT_3 + ADC10ON + ADC10IE; //using Vcc and gnd for reference, 16 clks/sample, turn ADC on and enable interrupts
for( int a = 100; a > 0; a-- ); // delay to allow reference to settle, might not be necessary
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
__bis_SR_register(CPUOFF + GIE); // LPM0 with interrupts enabled, this means that it enters low power until ADC conversion is done
results[1] = ADC10MEM; //copy ADC results to y data
ADC10CTL0 &= ~ENC; //reset encode bit
//read z: z is A2 which is P2.2
ADC10CTL1 = INCH_2 + ADC10DIV_2; //set ADC to A2 with clock divide of 2, we might not need the clock divide
ADC10CTL0 = SREF_0 + ADC10SHT_3 + ADC10ON + ADC10IE; //using Vcc and gnd for reference, 16 clks/sample, turn ADC on and enable interrupts
//for( int a = 100; a > 0; a-- ); // delay to allow reference to settle, might not be necessary
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
__bis_SR_register(CPUOFF + GIE); // LPM0 with interrupts enabled, this means that it enters low power until ADC conversion is done
results[2] = ADC10MEM; //copy ADC results to z data
ADC10CTL0 &= ~ENC; //reset encode bit

ADC10CTL0 &= ~(REFON + ADC10ON); // turn off A/D to save power

data_x = results[0];
data_y = results[1];
data_z = results[2];
msg[0] = data_x&0xFF;
msg[1] = (data_x>>8)&0x03;
msg[2] = data_y&0xFF;
msg[3] = (data_y>>8)&0xFF;
msg[4] = data_z&0xFF;
msg[5] = (data_z>>8)&0xFF;

But when i changed my SREF_0 to SREF_1 or SREF_2...etc The end point device cannot communicate with Access point

what is the problem?