Unfortunately, this is almost always the result of an internal hardware defect.
Sadly, this is extremely common in these onkyo receivers, which have some known hardware and design faults that resulted in extremely high failure rates of the hdmi board. What this means is that the circuit board inside the receiver that processes the hdmi signals has failed, and would have to be replaced.
The one thing you can try here is a microprocessor reset:
Power the unit off (standby mode)
then press and hold down the CBL/SAT button while powering back on
If still no change, it would unfortunately confirm a hardware fault, which would require repairs to correct.
To give you an idea, that repair will be in the $400-450 range. I would not consider that practical, when you can buy a brand new and updated receiver with a fresh warranty for the same price or less.
As an alternative, you can bypass the receiver entirely for video, and route all your devices to the tv directly via hdmi. Then run a separate optical cable from the tv back to the onkyo for sound.
Otherwise, depending how you'd like to proceed, I can help with finding a repair shop or recommending replacements for you.
Best regards, ***** ***** for the news,