USB-C and Thunderbolt 2 Adapter

I have a 2014 Mac Pro with Thunderbolt 2 connectors. I also have an Apple 27 inch monitor from that same period which uses a Thunderbolt 2 connector - not only for video but the monitor also pulls power through the Thunderbolt 2 connection. This is working fine.

I recently purchased an SSL audio interface that only pulls power through either a USB-A or USB-C connector. It does not have a separate power chord or connection. The audio interface works just fine on a two-year-old MacBook pro with USB-C.

I bought a Thunderbolt 2 to USB-C adapter to connect the audio interface to the older Mac Pro, however the audio interface cannot seem to get power through it. Any suggestions?