Relax User Restrictions
By default, only users with specific administrator privileges (i.e. the userrole xm.urlrewriter.admin as of v14.2, xm.repository.admin in v14.0-14.1) can access the URL Rewriter rules in the Content application.
The relevant configuration in the repository is as follows:
/hippo:configuration/hippo:frontend/cms/cms-browser/urlrewriterTreeLoader: hipposys:userrole: xm.urlrewriter.admin
It's possible to relax this restrictions by setting the hipposys:userrole property on the above node to a different userrole, for example xm.content.user for all users who can access to Content application.