ir blaster stopped working

to turn the tv on and off uses the ir blaster function, if that has stopped working then you may need to retrain it, all the xbox's in my house still work fine with turning the tv on and off viaa the IR blaster.

Did you setup you cable box in the OneGuide/tv settings section? Make sure the ir sensor is exactly on the ir receiver of you cable box, if RS off even a few mm it could stop it from working. You made sure your purchased a ir blaster wire and not a ir
receiver wire? If the the model of you cable box is in the Xbox one settings when you set it up then it should work, just make sure you are directly on the ir receiver of your box.

I use a cable in the livingroom because the Kinect blaster doesn't work for some reason so I have a 3 way Ir blaster wire that works grea but as I said you need to put it directly on your ir receiver for your cable box and if you want to control your tv
you need a cable with atleast 2 ir blasters and fix them to both your tv ir and cable box ir receiver.

I spoke too soon. When I hold the power button down to shut off the xbox, the next time it's turned on, it turns on the TV. Then the next time after that I turn on the Xbox, it doesn't turn on the TV. It seems the only time after the Spring 2017 update
the Xbox turns on a TV is after it's shut off holding the power button.

Looks like I'm not the only one after looking at the message boards :/

Have you tried a
power cycle? Just hold the power button for 10 seconds so the console fully turns off, then turn it back on.

I have to admit I was skeptical at first thinking what is a power cycle gonna do? But I tried it and what do you know, it worked! Thanks so much!

Have you tried a
power cycle? Just hold the power button for 10 seconds so the console fully turns off, then turn it back on.

Before I got the Xbox One S, my original Xbox One had IR blasters that controlled my TV. Occasionally, turning my console on wouldn't turn the TV on as well. Had to give my console a power cycle when that happened to make it work again. Sometimes you have
to "refresh" the console when you have it set to Instant-On (in the power settings).

Hope this helps!