Always start here, using another Wi-Fi client to determine which is the likely culprit, the network or the client.
When Wi-Fi is on, a signal indicator appears at the top right corner of your home screen.
Properly connected Wi-Fi takes precedence over mobile broadband, but it can be helpful to disable your device's mobile network connection while debugging Wi-Fi.
Note that whenever you're trying to connect an Android Wi-Fi client to any network name, status is displayed on the Wi-Fi Settings panel, in the row labeled Wi-Fi.
A fundamental component of RADIUS is a client's validation of the RADIUS server's identity.
This is accomplished by hosting a certificate on the RADIUS server that has been validated by a trusted Certificate Authority (CA).