1. Are you sure you followed [this step](https://gluu.org/docs/casa/installation/installation/#apply-patch) when you installed?
If you didn't you can still do so:
- stop casa service (service casa stop)
- cd to /opt/gluu/jetty/casa/webapps
- wget https://ox.gluu.org/maven/org/xdi/casa/3.1.6.Final/casa-3.1.6.Final.war
- mv casa.war casa.war.bak
- mv casa-3.1.6.Final.war casa.war
- start casa (service casa start)
2. Where did you see a broken link? Can you send me a screenshot / link to that page?
Let me know if that helps.