I have an Apple Time Capsule, and have been able to back up to it without a problem for the past few months. However, today I found I cannot connect to the Time Capsule from Finder, though it appears there, when I click "connect as...", it takes a few seconds and then reports connect failed, "the server may not exist or it is not operational at this time. Check the server name or IP address and your network connection and try again".
When I check Time Machine, it says the last backup failed because "the backup volume could not be mounted".
The strange part is, the Time Capsule is also my router, and I am able to use the Time Capsule as a wireless access point without a problem. Any ideas?