The following are some common reason for a cache disconnect.
Client-side causes
* The client application was redeployed.
* The client application performed a scaling operation.
* In the case of Cloud Services or Web Apps, this may be due to auto-scaling.
* The networking layer on the client side changed.
* Transient errors occurred in the client or in the network nodes between the client and the server.
* The bandwidth threshold limits were reached.
* CPU bound operations took too long to complete.
Server-side causes
* On the standard cache offering, the Azure Redis Cache service initiated a fail-over from the primary node to the secondary node.
* Azure was patching the instance where the cache was deployed
* This can be for Redis server updates or general VM maintenance.
