Many Zmanda Cloud Backup with Amazon S3 customers have experienced upload failures in recent days. The error returned is: Cloud communication error[CLOUD_ERROR_SignatureDoesNotMatch].
This is a problem on Amazon's end. We are working with them closely to see that it is resolved. All versions of ZCB are affected.
Until Amazon fixes the issue, we ask that ZCB customers use the workaround described in Error: Cloud communication error[CLOUD_ERROR_SignatureDoesNotMatch]. If you would like to be notified when the solution is found, please open a support case.