A user device registers with a proxy-call session control function device (P-CSCF) associated with an Internet protocol (IP) multimedia subsystem (IMS). The user device forwards a request to the P-CSCF requesting a session via the IMS for an IMS call. If a response to the request is not received from the P-CSCF during a time period after forwarding the request, the user device attempts to newly register with the P-CSCF. If the new registration is successful, the user device re-forwards the request to the P-CSCF. Otherwise, if the new registration with the P-CSCF is unsuccessful, the user device registers with a different P-CSCF and forwards the request to the second P-CSCF.