If you already use an ASP-hosted Zimbra system and face problems, here are quick fixes for common issues:
Are they using the open-source version or the Network Edition? The Network Edition gives you ActiveSync, multi-server setup, and backup APIs. An ASP should clearly state which licensing model they use. asp ct zimbra mail
This separation allows providers to scale horizontally. If storage is running low, you can add a new Mailstore server without touching the MTA or LDAP servers. If you already use an ASP-hosted Zimbra system
If you are an ASP planning to offer Zimbra hosting (or a business setting up a self-hosted ASP model), follow this checklist. follow this checklist.