Allowing HTTP Header Content Type */* in Azure WAF Rules

Question

I am trying to call the Azure-hosted API endpoint using a 3rd party application. Application sends the HTTP request with the header values ContentType = "*/*";

Azure Application Gateway WAF blocks the request showing the below diagnostics logs.

I am aware that, I can add an exclusion in the Web Application Firewall settings, however, I am not able to extract the Request Header Name since the logs do not show the value due to the wildcard(ContentType = "*/*";) content type sent by the 3rd party app.

I added the below rule, but it is still blocking the request.

How can I allow the request via the AGW?

Please find the logs below.

Thanks in advance.