@csikiedit
Have you got an aerial plugged into the Pro box that will give a picture OK when plugged directly into the TV?
The message from my 4K but not Pro YouView box when I pull the aerial is ‘Your TV signal is weak or lost’, plus some further help; ‘No Signal!’, unless you are paraphrasing, sounds like a message from your TV to say there is nothing there at all, as happens if I disconnect the HDMI cable from the box.
Are you using an HDMI cable between box and TV? Can you try another one? Can you try an alternate HDMI input on the TV, even if you have to temporarily remove another device to try this?
It’s not impossible that two consecutive Pro boxes would be faulty, but it is very unlikely. And though I imagine BT must have walked you through correct setup before agreeing to replace the box (yes?) it does seem very much like an issue with configuration, the cable, or the TV, and not another box failure.
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*** Longtime YouView box owner, BT Broadband customer, finally an EE TV subscriber ***
