title: Azure B2C API Connector fails with http: 400 There was a problem processing your request. Please try again
body: <p>I've connection issues between Azure B2C API Connector and a CAPTCHA Web-Service.
  Everything worked well until 31.12.2021. Not sure about the first week in January 2022.</p>
  <p>All services, whenever offered by Microsoft are in a Swiss data center. Since January I'm playing Mail Ping-Pong with the MS Support Team :-(</p>
  <ul>
  <li>Azure B2C calling a service via Azure Front Door <strong>in detection mode</strong> fails.</li>
  <li>Azure B2C calling a the service &quot;direct&quot; works.</li>
  <li>Calling the service using Postman works via the Azure Front Door and Direct</li>
  </ul>
  <p>I don't use custom policies, so no logs. Or maybe I don't know where to look?
  Azure unfortunately only returns a HTTP 400 with the message &quot;there was a problem&quot;.
  The Service is not receiving any get request.
  According to the Firewall log, no request is blocked.</p>
  <p>Would be happy for any hints. My personal best guess - Microsoft did renew the X.509 SSL certificates and forgot one due to the 31.12.2021</p>
  <p>But would be happy for anything else that might had changed?</p>
  <p>Thanks a lot.</p>
  <p><a href="https://i.stack.imgur.com/Qjgch.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Qjgch.png" alt="enter image description here" /></a></p>