Are you using GNURadio v3.10? If yes, our OOT modules were developed on v3.9 and will require porting to 3.10. We currently have this as a TODO, so it is left as a customer exercise until we can make time for this. There are some resources that might help, for instance, https://wiki.gnuradio.org/index.php/GNU_Radio_3.10_OOT_Module_Porting_Guide