Since you did not provide much information, could you please try below and share the details.
- What is the version of the Unleashed? - Is it just one client unable to connect or all the clients are not able to connect to Guest WiFi using guest pass? - Are you using single guest pass for all the users or creating different guest passes for different users? - If some specific clients are unable to connect, check if clients are able to connect to guest WiFi and getting a valid IP and portal page. - If they are getting portal page and guest pass is invalid then try creating a new guest pass. - If clients are not at all getting guest portal page then it could be due to network configuration changes or port block on firewall between client IP subnet to AP IP subnet. - Any recent configuration changes?