You’re not telling where we should look on your site
The code linked is ok, it means any element of that class hovered by the cursor will get the defined image as a cursor. But you can google for image limitations. They’re not the same for each browser. Try with a 32 x 32 PNG image. Be sure to make the image stick to the upper left corner of the artboard.
Custom cursors aren’t recommended. They look horrible most of the time and users don’t really like to have their cursor changed to something fancy. But you decide Cursor design is hard. It’s small and need to be black with a white outline to be visible at all time. I tried many times and was never satisfied with the result.
I made an example for you on that site (it’s obvious), but it’s very poor with a very large cursor that’s not optimized or refined at all.
Here’s the image used (too big, no outline):
cursor: url('https://daks2k3a4ib2z.cloudfront.net/5931952fcb454512c039a2b4/5a204d414ee3d200016a622e_mic32.png'), default;