Before moving onto using Collect with Aggregate, you need to ensure if Aggregate is working fine from the browser.
Try this:
- Shutdown tomcat.
- Rename ODKAggregate.war as ROOT.war
- Go to /usr/share/tomcat8/webapps directory, and delete everything.
- Copy ROOT.war file to this folder.
- Restart tomcat8.
You should be able to see Aggregate, if you have configured all the other steps perfectly fine.
Regards,
Saad