May i know on what operator its not working Cosmote Greece or Vodafone ?
Are you using both the mobile antennas provided . Its highly recommended to use both the mobile antennas.
I see in the troubleshoot file RSRP value is poor and at this value of -105 there will be disconnection :
AT+QENG="servingcell": +QENG: "servingcell","NOCONN","LTE","FDD",202,01,311701F,189,3194,7,3,3,1020,-105,-9,-80,17,-
Have you tried using the same sim card in your phone or other device just to be sure if it has enough data in it?
Please let me know.