Problem

To resolve this issue, increase the maxHttpHeaderSize value in the Tomcat configuration.

To increase the maxHttpHeaderSize value:

1. Navigate to the Tomcat Configuration Directory:
   Path: <codeInsightInstallDir>/tomcat/conf
2. Edit the server.xml File:
   1. Locate the <Connector> tag under the (FlexNet Code Insight) FNCI SSL section.
   2. Modify or add the maxHttpHeaderSize attribute.
   3. Increase the attribute size to "65536" i.e. 64 Kilobytes. 
   
   The configuration should look like the following:
   

   <!-- FNCI SSL: Edit this section to match your certificate information -->
   <Connector protocol="org.apache.coyote.http11.Http11Protocol"
              port="8888"
              minSpareThreads="25"
              enableLookups="false"
              disableUploadTimeout="true"
              acceptCount="100"
              maxThreads="150"
              maxHttpHeaderSize="65536"
              scheme="https"
              secure="true"
              SSLEnabled="true"
              keystoreFile="codeinsight.jks"
              keystorePass="codeinsight"
              keyAlias="codeinsightAlias"
              keyPass="codeinsightPass"
              clientAuth="false"
              sslProtocol="TLS" />

3. After saving the changes, restart the Tomcat server to apply the new configuration.

NOTE: The recommended value for maxHttpHeaderSize is 16384 bytes as per the Code Insight Installation and Configuration Guide. However, some API calls may require a larger buffer size, up to 65536 bytes (64KB)—to function correctly without triggering this error.

NOTE: The following issue is only observed in an SSL-enabled environment.

After performing the suggested steps, the product should work properly and as expected.