GCP api gateway SSLV3_ALERT_HANDSHAKE_FAILURE

Question

I'm trying to create a small project to get to know the google cloud API gateway better.
I've created a gateway with the below config file that suppleid with the gateway docs and I made some adjustments according to my needs.

swagger: '2.0'
info:
  title: test gateway YAML
  description: test API Gateway
  version: 1.0.0
schemes:
  - https
produces:
  - application/json
paths:
  /stackoverflow:
    get:
      summary: get stackoverflow
      operationId: stackoverflow
      x-google-backend:
        address: https://stackoverflow.com
      responses:
        '200':
          description: A successful response
          schema:
            type: string
  /other_web:
    get:
      summary: get Other
      operationId: Other_web
      x-google-backend:
        address: https://Other_web.com
      responses:
        '200':
          description: A successful response
          schema:
            type: string

when I'm visiting the https://GATEWAY_URL/stackoverflow route everything works as As expected and im getting the stackoverflow homepage.
When I'm visiting the https://GATEWAY_URL/other_web route ive got this error:

{
"code": 503,
"message": "upstream connect error or disconnect/reset before headers. reset reason: connection failure, transport failure reason: TLS error: 268436496:SSL routines:OPENSSL_internal:SSLV3_ALERT_HANDSHAKE_FAILURE 268435610:SSL routines:OPENSSL_internal:HANDSHAKE_FAILURE_ON_CLIENT_HELLO"
}

That is odd because when im visiting https://Other_web.com directly (through chrome/postman) and not through the gateway I got the page and no error is shown. just through the Gateway, I'm getting these errors. Any ideas why this is happening ?
thank you all :)