I'm sorry you encountered an issue.
I'm guessing you are referring to the blue "Pause", "Resume", "Toggle Log"...etc buttons below the game ?
Those come by default when I make a web build with Unreal. I don't really want them there honestly, so I added a pause button myself (you need to press Tab).
But from what I've seen it seems to work ? It's really unintuitive because the button to "Pause" and "Resume" are two different ones, but its operational on my pc.
I've only tried with Firefox and Chrome tho, maybe other browsers do have issues.
And thanks for the feedback of course !