Ok, couple of thoughts. Click on Connector: down arrow and see what other choices are present if any, but don't think that is an issue. The way I sorta understand it is that by checking in Choose a device for sound input:
Monitor of ...... option it creates a virtual type microphone that records the output of the speakers.Maybe check in Output tab to see what connector shows. My previous image shows settings applying to my laptop's installed devices, yours will be different. Try switching to Monitor (possibly FHD may mess up??) Just guessing.