mac mini hdmi port won't connect anymore

I use 2 external monitors on my mac mini, one is connected through a usb-c hdmi adaptor the other is connected directly in to the mac mini's hdmi port. I awoke the computer from sleep this morning and the monitor that is plugged directly into the hdmi port will no longer display. switching which monitor is using the adaptor I can confirm that both hdmi cables and displays still work, but whichever monitor is using the standard hdmi port refuses to display.

I have tried going to system preferences -> displays and hitting the "detect displays" button but that has not helped. I have also tried restarting the computer twice, as well as unplugging and the monitor's power and display cables and re attaching them. So far no luck on getting a monitor to display using the standard hdmi port, while the usb-c port works fine.