We've seen a couple of cases where cbbackupmgr will fail to perform a backup with an "unambiguous timeout" error. This can happen when the given user doesn't have the correct permissions to perform a backup (e.g. the RBAC role lacks DCP_DATA_READER).
gocbcore is not correctly propagating errors to the application though the 'WaitUntilReady' function (see
GOCBC-905 for more information). Internally gocbcore continues trying until we have reached the timeout (which we set to 60s).
We must wait until the fix has landed in gocbcore then we can update the manifest. There should be no code changes in cbbackupmgr.