Can't add custom font

Hi everyone, I’m having an issue uploading a customer font. I’ve followed the guidance given on a few forum posts, but am still getting the error below:

Here’s the content of my css file:

@font-face {
font-family: Windsor Pro;
src: url(‘//f935ff77e16ed23551f6904c576fc597.cdn.bubble.io/f1716512186802x894494730075256800/WindsorProRg.TTF’);
}

Can someone advise where I’m going wrong? Many thanks, Debbie