For the inbound SOAP calls, a '400 Bad Request' error message is returned if the request header size is more than 8 KB.
Release or Environment
The default maximum header size for request and response headers is 4096 on older versions of tomcat (5 for example), for tomcat8 it is 8192 (8KB). If the request header size is more than 8 KB, the platform would return a '400 Bad Request' message.
Ensure that we are limiting the header size to 8 KB. Remove unnecessary parameters from headers.
https://tomcat.apache.org/tomcat-8.0-doc/config/http.html (Refer to maxHttpHeaderSize)
The maximum size of the request and response HTTP header, specified in bytes. If not specified, this attribute is set to 8192 (8 KB).