Exception thrown at toolbar.vm

I created a Crowd plugin, configured web item in atlassian-plugin.xml.

Open the pages with URL localhost:4990/crowd, the web item label is not displayed and exceptions exist in the log file.

2017-03-23 09:39:38,251 http-bio-4990-exec-5 ERROR [[Catalina].[localhost].[/crowd].[servlet-module-container-servlet]] Servlet.service() for servlet [servlet-module-container-servlet] in context with path [/crowd] threw exception
com.atlassian.templaterenderer.RenderingException: org.apache.velocity.exception.MethodInvocationException: Invocation of method 'getDisplayableLabel' in  class com.atlassian.plugin.web.model.DefaultWebLabel threw exception java.lang.NullPointerException at /templates/toolbar.vm[line 96, column 161]

Caused by: org.apache.velocity.exception.MethodInvocationException: Invocation of method **'getDisplayableLabel**' in  class com.atlassian.plugin.web.model.DefaultWebLabel threw exception java.lang.NullPointerException at /templates**/toolbar.vm**[line 96, column 161]

Caused by: java.lang.NullPointerException

could you help to find the solution?

What does your webItem look like (feel free to anonymize it)?

Thank you for your reply.

The webItem for custom backup operation looks like:

<web-item key="MyCustomBackupKey1" name="MyCustomBackup1" section="administrationnav"
	weight="130">
	<label key="MyCustomBackup1" />
	<link linkId="adminUPM">/console/secure/plugins/upm/default.action</link>
</web-item>

I haven’t look at crowd’s source code yet for this but make sure that your label rage has a text value. I.e.:
something
Or that MyCustomBackup1 is in your i18n properties file.

OK, I will check it.
Thank you for your time.