Atomicorp.com WAF Rules: POST request must have a Content-Length header
A valid POST request should have a Content-Length header. POSTS that do not include this can be indicative of an attack.
This can be triggered if an application is poorly written and does not include this header. If you must disable this rule, you should disable it only for that specific application and only from trusted IP addresses. The best option is to fix the application so that it includes this Header.
If you believe this is a false positive, it is recommended that you report this to our security team can determine if this is a legitimate case, or if its clever attack on your system. Instructions to report false positives are detailed on the Reporting False Positives wiki page.