2011 iMac G-DRIVE with Thunderbolt 3

I am trying to use this drive with my 2011 iMac. I used this same setup with my MacBook Pro (2015) and it worked fine. I have the USB-C to thunderbolt 1/2 adapter with a thunderbolt 1/2 cable connected to the iMac. Again just like my MacBook pro. The drive will not load on the iMac. Loads fine on my 2015 MacBook pro and loads fine with a USB-C cable with my 2019 MacBook Pro. Is this a compatibility issue?

Update, just used my moms 2012 MacBook pro and it loaded up fine…

Update #2, I can connect the drive and use TimeMachine with a USB-C to USB 2.0 cord. I would assume the thunderbolt option would be faster.

Early Thunderbolt 1 and 2 are not powered and used for data only. Thunderbolt 3 / USC Type C is powered.