Those AC adapters are very prone to failure
*. And the HDMI sockets on those Chinese converters very finicky. That "dropout example" I recorded was me simply jiggling the HDMI and power cables a bit.
Also... don't be fooled by that "red light": it can come on even without a power supply connected, just with the current provided by HDMI.
So, first things to try: another HDMI cable and a new power supply.
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(*) Internally, whilst looking perfectly OK — at some point their voltage or amperage output drops, making the connected appliance malfunction.