IntraWeb 15.1.20 - Server Error with ASPX

[JohBer]

I suggest you check the incoming headers and all the fields being sent to your application....

Check for what exactly? Tracking the request with ServerController.OnAfterDispatch I get this. As you can see the request is handled and the ServerController reply is 200. Then when it leaves the Delphi code and is handled by the ASPX-wrapper is when we get the original Not a legal OleAut date-error.

Code:

Request:
GET /$/authenticate/
Connection: Keep-Alive
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.5
Cookie: ARRAffinity=30cb611841c421ca9865e15ff9883530e5700fa506c083101ca0e611c085dd20
Max-Forwards: 10
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0
Upgrade-Insecure-Requests: 1
X-ARR-LOG-ID: c0e3386e-5492-4c8a-b8d8-7428fb5840ee
X-Forwarded-For: 212.85.72.105:63740

Response (status 200)
Content-Type: text/html; charset=UTF-8
Set-Cookie: IW_SDFOnLine=Y2s7yXU~4WOn2tLpRJ5swuF4rEy_1; Domain=; Path=/; Expires=Sat, 25 Apr 2020 08:47:08 GMT

Obviously something in the response makes the Intraweb's ASPX-wrapper complain. I'm at a loss about how to figure out what exactly that "something" is without more assistance or access to its source. As it is we can't use IW 15 at all. Given we have an IntraWeb Ultimate Edition license I don't see the problem with getting access to the ASPX-wrapper source, but perhaps there is a very good reason...