When I tried to do simulate with the ethers client, my request got blocked by cors on sepolia relay.
I was using it on next.js.
Access to fetch at 'https://relay-sepolia.flashbots.net/' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
When I tried to do simulate with the ethers client, my request got blocked by cors on sepolia relay.
I was using it on next.js.