Cloud Run External Call SSL error

[rafaca]

Hello!

I have a API on cloud run developed using .NET 6. The API is working great, most routes are working as expected.

On my API I have some routes that needs to check on a external service making REST requests (mostly POST calls).

The problem is: when I take my API to cloud run, those routes don't work as expected. I receive an SSL ERROR during the request.

On my computer, coworkers computers (different ISP) and on a GCP VM the API work as expected.

The problem only occurs on cloud run.

{
  "success": false,
  "metaData": null,
  "dataHora": "2022-04-25T17:09:16.683683+00:00",
  "errorMetaData": {
    "stackTrace": null,
    "errorMessage": "Call failed. The SSL connection could not be established, see inner exception: POST https://************************/b1s/v1/Login",
    "innerError": {
      "stackTrace": null,
      "errorMessage": "The SSL connection could not be established, see inner exception.",
      "innerError": {
        "stackTrace": null,
        "errorMessage": "Authentication failed, see inner exception.",
        "innerError": {
          "stackTrace": null,
          "errorMessage": "SSL Handshake failed with OpenSSL error - SSL_ERROR_SSL.",
          "innerError": {
            "stackTrace": null,
            "errorMessage": "error:1425F102:SSL routines:ssl_choose_client_version:unsupported protocol",
            "innerError": null
          }
        }
      }
    }
  }
}

[osvaldolopez]

This post already has an answer in this Stack Overflow post.