All backups are missing

Turned my Mac on this morning and was told that I had not performed a backup in 1690 days. WOW! I bought my machine in June 2013 and am being told my last backup was July 24, 2013. I go into the Time Capsule and sure enough, nothing is there. This only happened recently because I performed a backup a few weeks ago. I have done nothing special with the Time Capsule. Just basically installed it and started using it. When I try to connect to the backup disk, I enter my password and am told "Time Machine can't connect to the backup disk. OSStatus error 5". what to do??