Hi @tkddnjs825,
In addition to Alex's question above, could you also please share which version of voxl-elrs is being used on each voxl2? The voxl-version command should list the versions of each installed package.
Can you also please confirm that in the voxl-px4 configuration file on the voxl2 that is not able to communicate with the ELRS receiver that the RC type is set to CRSF_RAW, like this: RC=CRSF_RAW.
Furthermore, if you could share the output of voxl-elrs --scan from the voxl which is unsuccessful that would be helpful.
Thanks,
Max