Nothing working with XBEE S2C

Hello, I am trying to communicate two XBEEs S2C. Before, I have tried with S1 and I did not have any problems. Form my project I will use them with arduino, but for now, I would be happy if I get the modules to communicate.

I am using a XBEE dongle and an Arduino Shield (Arduino A000021 Xbee Shield w/o RF Module | Rapid Online), I have tried with this one and the older model, and the results are the same. This is plugged on an Arduino that has the microcontroller removed, since using it on the so called reset mode is sometimes problematic. I am aware of how to use the shitch, on usb when configuring the XBEE and XBEE for RF communication.

For communication, I have tried with both, the functions set on ZIGBEE TH Reg and 802.15.4 TH. As far as I know, the difference is on the topology of the net that they support, and any of these configurations should work with my modules. I would be grateful if someone could clarify this.

When using ZIGBEE TH Reg I set one device as coordinator and the other as end device, with JV enabled. When using 802.15.4 TH, have tried with one coordinator and one end device and with two end devices.

For the destination addresses I have tried different configurations: DH and DL being the same as the SH and SL of the other module respectively, DH = 0 and DL = FFFF on both modules, or just in one of them with the having both parameters set as 0. Also, leaving DH as 0 for both devices and using DL and MY, set as DL=1 nd MY=2 on one device and the opposite on the other.

PAN ID and Channel are the same in both modules.

I have set the default values and modified these parameters several times, to make sure I was not changing another parameter.

I have tried AT and API communication and never received a single packet on console.

The modules update the firmware without problems.

Thanks