Atomicorp.com WAF Rules: HTTP Smuggling Attack.
This attack combines transfer encoding and content length attacks. There is no legitimate traffic that uses this method, this is an attack.
There are no known False Positives for this.
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.