My last comment was meant only to address the fact that your hardware IS new enough (has an sd slot), and clarify this feature works only with the sd card (not the built-in flash).
There are a few more steps/details to the process, check out the SNAP PAC R-Series User’s Guide, search for “testing a strategy” (step 5 talks about the rules for naming, must end in .cdf, for example).
Also, some changes were made to that functionality in the last few years. Do you know the firmware versions of your remote SNAP-PAC-Rs? (Vs. what the one you’re using for testing?) If they’re not all the same, you might also want to check out the info in that manual about updating firmware from the sd card.