Can you help me get Instagram sound working again?

On my laptop? Certain videos have a little speaker icon crossed through in the bottom right-hand corner. Tapping the video only stops & starts it, the sound stays off. And yet the same video will play fine on my phone. Not all videos are affected. I don't understand it. I've gone through the troubleshooting thing & I'm still none-the-wiser.. There is nothing wrong with any other aspect of sound on my laptop. I'm sure a button just needs pressing somewhere...