This is from the
support section over at AvantGo:
Planned Maintenance Outage: We are planning an outage for the weekend of April 29, 2005 at 17:00 PDT through May 1, 2005 at 23:59 PDT to perform scheduled maintenance. Users will not be able to sync or login to my.avantgo.com during the outage.
Hence one more reason not to use a centralized solution like AvantGo.