Ensure that you have the free base-level registered membership of Avaya DevConnect Program. For information about Avaya DevConnect, see Avaya DevConnect Program Guide available on https://support.avaya.com.
Ensure that the following certificates are installed and trusted on the iOS device:
A trust certificate for System Manager that manages the cluster containing Avaya Mobile Communications Snap-in.
A trust certificate for Avaya Aura® Device Services using the link: https://<Avaya Aura Device Services_FQDN>/acs/resources.
A trust certificate for Avaya Aura® Web Gateway using the link: https://<Avaya Aura Web Gateway_FQDN/csa/resources/tenants/default.