cache-control is not allowed by Access-Control-Allow-Headers in preflight response

[dalesupa22]

Hi guys,

I am trying to validate a valid json Blockcerts credential V2 and Im getting the following error:

Access to XMLHttpRequest at 'https://api.etherscan.io/api?module=proxy&action=eth_getTransactionByHash&txhash=0x21a53b030da894ce42b1f18483bc59ef4c3e8f9d2b5b36b3769954487fe73b2b&apikey=XXXXXXXXXXXXXX' from origin 'https://www.blockcerts.org/' has been blocked by CORS policy: Request header field cache-control is not allowed by Access-Control-Allow-Headers in preflight response.

After a long time dealing with it... I found that the problem🐞🐞🐞 was the following code:

.setRequestHeader("Cache-Control","no-cache, no-store, max-age=0")

Please remove this part from the code in order to make it work again.

[lemoustachiste]

Hi @dalesupa22,

I think this issue has been resolved although I found out about it through another channel.

Do you mind checking again if it has been fixed for you?