Multipart requests getting blocked by the Azure WAF 200003

Hi richie , 

First of all thank you for the detailed reply!
I followed the instructions you sent the link to and then compared raw requests from both ReadyAPI and Postman. There were some differences in the requests, so I made some modifications, but unfortunately still didn't manage to make it work.

I am attaching raw requests. the only real difference I see is the 'boundary' parameter, so I will try to somehow modify that.

Postman request (that one works):

POST [Redacted] HTTP/1.1
MIME-Version: 1.0
Connection: Keep-Alive
Accept-Encoding: gzip,deflate,br
Authorization: Bearer [Redacted]
User-Agent: PostmanRuntime/7.37.3
Accept: */*
Postman-Token: [Redacted]
Host: [Redacted]
Content-Type: multipart/form-data; boundary=--------------------------362113083232692374548533
Content-Length: 160138
 
----------------------------362113083232692374548533
Content-Disposition: form-data; name="attachment"; filename="test.png"
<test.png>
----------------------------362113083232692374548533--

ReadyAPI request:

POST [Redacted] HTTP/1.1
Accept-Encoding: gzip,deflate,br
Content-Type: multipart/form-data; boundary="----=_Part_498_280555933.1715003877236"
MIME-Version: 1.0
Authorization: Bearer [Redacted]
Accept: */*
Content-Length: 160089
Host: [Redacted]
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.5.14 (Java/17.0.10)

------=_Part_498_280555933.1715003877236
Content-Disposition: form-data; name="attachment"; filename="test.png"

‰PNG