There are a couple ways to give custom hold music inside of UCCX. You can use call control groups, or play prompts. I go over the pros and cons of both ways to achieve custom music on hold.
UCCX call control groups and music on hold
UCCX agents unable to login to CAD (cisco agent desktop)
UCCX agents may get the error that they cannot login into CAD (cisco agent desktop) because one or more of the IP addresses have changed.