USB on back of Acer XR342CK Pbmiiqphuzx 34" 21:9 Curved IPS Monitor not working?

Hi. My boss has a Acer XR342CK Pbmiiqphuzx 34" 21:9 Curved IPS monitor. She uses a Microsoft Wired Desktop 600 USB keyboard and mouse (https://www.bhphotovideo.com/c/product/603375-REG/Microsoft_APB00001_Wired_Desktop_600_USB.html) and plugs them into the two USB ports on the back of the monitor. Recently the mouse and keyboard have suddenly stopped working. This happened once before and then they started working again spontaneously. We tried unplugging/plugging things back in and turning everything off. Maybe the batteries need to be replaced but it's odd that both the keyboard and mouse stopped working at the same time, which leads me to believe it's the monitor. Could this just be a hardware issue or something else?