For some reason, my headset works fine as an output, but TS recognizes it as an input but it says it is invalid and the text is red.
With no details given i say your device is broken.
Please give at least some details about your device, client , operation system and a client log.
It usually is red when the device previously selected is no longer available. Check the drop-down if the same device is present (maybe under another name).
This can happen e.g. because of Windows updates.