Echo processes some words as reserved commands, so you can’t use them as the names of home automation devices. For example, I used to have a switch called “power” but that is now an echo reserved word. So if I say turn power off, instead of turning off the switch named power, echo turns itself off.
The same is true for “play” and “pause.”
There’s no list of these anywhere that I’ve seen, you just have to figure them out because you get exactly the result you got – – echo hears the phrase correctly, but doesn’t apparently do anything.
We do have a topic which discusses the ones that we found so far. But the short answer is just rename “pause” to be something else. Some people have found that “pause Roku” or “pause TV” will work when just “pause” doesn’t. I use “hold” Now just because I was trying to pick something that echo wouldn’t be likely to reserve in the future.