How to troubleshoot the issue with Polls for Confluence app after upgrade/migration of the Confluence to 7.19.18 and above versions of 7.x

\uD83D\uDCD8 Instructions

Follow the below steps:

Navigate to the Confluence server installed location at this path
<confluencePath>/atlassian-confluence-7.19.18/confluence/WEB-INF/classes/velocity.properties
Make below changes to the file velocity.properties
- Go to introspector.allowlist.classes
- Add this line to the existing values in the new line com.opensymphony.xwork.util.XWorkList
Sample reference:
```
java.io.ObjectInputValidation,\   
com.opensymphony.xwork.util.XWorkList,\
net.sf.hibernate.proxy.HibernateProxy
```
Stop and start the server.