Seth,
Any chance you can check if the ordinary SIM card works? Just to be sure that the absence of a connection depends on the SIM card. As far as I see, both Hologram and Twilio provide only M2M SIMs.
With some M2M SIM cards, you can enable the standard SIM card mode with the help of the provider. Such configuration may vary from carrier to carrier, that is why we can’t be much of a help with the Twilio in particular.