Open Firebase Project > in project overview (project settings) > Service accounts >Manage service account permission.

click on terminal on top right and machine is running.

After that, type these:

echo '[{ "origin": ["*"], "method": ["GET", "HEAD"], "maxAgeSeconds": 3600, "responseHeader": ["Content-Type", "Access-Control-Allow-Origin"] }]' > cors.json

then write these and replace the address (football-abcd) with your firebase storage bucket.

gsutil cors set cors.json gs://football-abcd.firebasestorage.app

Congratulations.

Setting CORS on gs://football-abcd.firebasestorage.app/...