Issue while connecting Cube orange plus with custom qgc

Hi, I cloned the github repo of qgroundcontrol and tried making my custom qgc. now i am trying to connect cube with qgc but its not connecting.
In my device settings it shows MAVLINK port COM5 but while adding in comm list i have no option to click on com5, only com1 and com6 are in the list. pls help

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