The iPad will display "Cannot authenticate"

If the credentials are correct and the WiFi is connected, then the IP is blocked, this will prevent connection from the specific device.

To repair you can unlock the IP link within the processor configuration.

1. To block/unblock a user

1. Select the applicable user and click on the Block/Unblock button:
   
   
   
   

2. In the Block/Unblock dialog box, select the BLOCK user or UNBLOCK ALL users radio button, as applicable, and click the OK button: