xbee pro s2c digimesh 2.4 trace not found

I tried to connect 2 xbee pro s2c digimesh 2.4. One setup with xctu in pc and the other plugged with an arduino. I tried to test the reliability of the communication and send repeatedly via loop on arduino to send packet to xtcu. XCTU also can send packet to arduino without a problem. I got successful sending packet for a few hours before it get ‘stucked’. Arduino itself seems keep looping since I see the status led keep blinking every few seconds. But xctu didn’t receive the packet anymore. I have some probability of the errors as follow:

  1. Baud rate of arduino and xbee may not sync anymore?
  2. Arduino error?
  3. Xbee on the arduino error?
  4. Xctu error?
  5. Xbee on the xctu error?

And here for now here is my result of test:
2. Arduino error? this should be not a problem, since I still see the status led blinking.
4. Xctu error? I don’t think so, since I can made some at command query, so it must be working fine.
5. Xbee on the xctu error? Communication between pc and xbee just fine, so I don’t think this is the caused.

this left me with the rest 2 possibilities:

  1. Baud rate of arduino and xbee may not sync anymore? Maybe… I skip this one because the number 3 seems to be the best candidate.
  2. Xbee on the arduino error? This looks to be the most possible why send is failed. I tried to send packet from XCTU and it failed with delivery status of “no route found”.

On arduino, I just use the example tx skecth from Andrewrapp in github:
https://github.com/andrewrapp/xbee-arduino/

And xtcu is from the digi itself. So I don’t have any clue why this is not working after few hours. The only way to make it again is unplug the arduino power and plug it again.
I need a reliable communication. I don’t think restarting system after few hours is a good solution.

Need help. Thank you.