Hello,

I am trying to exec callGetMethod from the browser and am getting this error:
Access to XMLHttpRequest at 'https://testnet.toncenter.com/api/v2/jsonRPC' from origin '...' has been blocked by CORS policy: Request header field x-ton-client-version is not allowed by Access-Control-Allow-Headers in preflight response.

I'm using apiKey for TonClient() function

Help please fix it