I had the same problem while using an I-Pad (still kinda have the issue). However, if i started a trainer road workout, unplugged the direto, plugged it back in, it would work. SOMETIMES i needed to also unpair the device.

I switched to just using a Macbook and it worked fine, so i think the issue is with ios. I assume trainer road or direto will come out with some firmware that solves the issue in the near future.