When I try to switch b from hdmi one to hdmi 4K on my projector it isn’t able to find a signal why is that?

When I try to switch b from hdmi one to hdmi 4K on my projector it isn’t able to find a signal why is that?
When I try to switch b from hdmi one to hdmi 4K on my projector it isn’t able to find a signal why is that?
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