A User Equipment (UE) comprises control circuitry and transmission and reception circuitry. The transmission and reception circuitry is configured to receive, from an Access and Mobility Management Function (AMF), a first configuration update command message including a rejected Network Slice Selection Assistance Information (NSSAI) including a Single Network Slice Selection Assistance Information for which a maximum number of UEs has been reached, a cause value indicating that the S-NSSAI is not available due to the maximum number of UEs being reached, and a back-off timer value for the S-NSSAI. The control circuitry is configured to start a timer with the back-off timer value for the S-NSSAI. The transmission and reception circuitry is further configured not to attempt to use the S-NSSAI while the back-off timer is running.