David,
There a few things in the coding that may go against both the HTTP and HTML standards, but before crafting convoluted reasoning I need further info:
- Can you tell me which request(s) generated the HTTP 400 error?
- It could also be of value to know the full HTTP status code (i.e., code + label) of the response to each request, and particularly to the POST.
- I need you to confirm that the header line "Host: URL:PORT" is exactly the same in *ALL* requests (data was anonymized for good reasons) because a host value not properly configured on the server typically generates a 400 error.
Pascal