Cannot open "Home Page" dashboard - error: "Status: 500 - Internal Server Error" (4248924)

When opening the "Home page" dashboard of an Oracle database the following error comes up:

"Status: 500 - Internal Server Error".

These errors were noted in the Foglight Management Server log:

1)
VERBOSE [main] STDOUT - Can not initial DBWClog level from the Registry:java.lang.Exception: Can not convert : DBWC_WARN,user@domain to DBWCLog_Level

2)
ERROR   [http-0.0.0.0-8080-55] com.quest.wcf.core.module.function.AbstractFunctionWithInputs - error executing script id=system:dbwc_globalview_severitycalculator.4 name="'Build Regvalues Map' from the System module Databases/GlobalView/severityCalculator"
message: com.quest.nitro.service.sl.interfaces.scripting.ScriptingException: com.quest.nitro.service.sl.interfaces.scripting.ScriptAbortException: script1000482: java.lang.NullPointerException
 in view: 'system:dbwc_globalview_oracle20quick20view.9' in top-level view: 'system:dbwc.16' for user: 'foglight'
javax.script.ScriptException: com.quest.nitro.service.sl.interfaces.scripting.ScriptingException: com.quest.nitro.service.sl.interfaces.scripting.ScriptAbortException: script1000482: java.lang.NullPointerException
 at com.quest.nitro.webconsole.services.ScriptServiceImpl.eval(ScriptServiceImpl.java:76)
Caused by: java.lang.NullPointerException
 at com.quest.qsi.javaGlobalView.logger.DBWCLogger.<init>(DBWCLogger.java:91)
 at com.quest.qsi.javaGlobalView.logger.DBWC_LogFactory.getLog(DBWC_LogFactory.java:200)
 at com.quest.qsi.javaGlobalView.logger.DBWC_LogFactory$getLog.call(Unknown Source)
 at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:40)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
 at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
 at script1000337.run(script1000337.groovy:7)
 at com.quest.nitro.s