Why am I not getting long range communication using Xbee868?

I ordered an Xbee868 development kit (PN: XK8-DMSB0) to evaluate the performance of Xbee868 modules for a project that I’m working on. I did the first test using XCTU’s Range Testing tool. I connected two modules together and started to gradually get them away from each other. The maximum distance at which they could reliably communicate was ~110m, beyond which they do not connect at all.

I conducted the test in an open field where the two modules were directly seeing each other and with and no obstacles blocking their way. The datasheet of the module mentions that the communication distance can reach up to 8km using a 2.1dBi antenna, which I suppose is the same type of antenna that comes with the dev kit.

This was my case and the range that I achieved was nowhere what’s specified on the datasheet. What could be the problem here?

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