adapter

Hi ya'll! I've got some issues with my 1621+ and I think there is no better place to be asking than here. I'd love to get some help please. I've got an iMac (2017, i7, 32GB Ram) connected via thunderbolt 3 (UCBC) to an OWC 10gbe to USB-c adapter. (This boy). The OWC is connected via CAT6 kabel...