After upgrading Tomcat, the customer is seeing the following error when opening Visualizer:
HTTP Status 404 – Not Found Type Status Report Message The requested resource [/CMDBVisualizer/externallaunch.do] is not available
Customer is able to telnet to the Visualizer port to confirm it is open.
Release : 17.2.RU10 and higher
Component : SERVICE DESK MANAGER
After following the section "CMDB Visualizer Interface may fail to launch with HTTP 404 Error" the error was resolved.
In another scenario, the pdm_tomcat_VIZ log contains the following error:
INFO: Deploying web application directory [C:\Program Files (x86)\CA\Service Desk Manager\bopcfg\www\CATALINA_BASE_VIZ\webapps\CMDBVisualizer]
Sep 07, 2022 3:12:32 AM org.apache.tomcat.util.digester.Digester fatalError
SEVERE: Parse fatal error at line  column 
org.xml.sax.SAXParseException; systemId: file:/C:/Program%20Files%20(x86)/CA/Service%20Desk%20Manager/bopcfg/www/CATALINA_BASE_VIZ/conf/context.xml; lineNumber: 3; columnNumber: 6; The processing instruction target matching "[xX][mM][lL]" is not allowed.
In the context.xml file referenced in the error above we see the following:
Issue was caused by the introduction of newlines at the start of the file. Ensure there are no extra lines or spaces at the beginning of this file.
Remove anything that exists there
The very first line should be:
<?xml version="1.0" encoding="UTF-8"?>
The save context.xml, restart the service, and try to access visualizer again.
Also Compare to a known working version of context.xml and check for any differences.