The reported error, "Proceed Ack Failed," occurs during backup configuration when there is a network drop, improper network connectivity, network timeout, or if the agent doesn't receive the initial handshake acknowledgment from the backup server within the stipulated time. By default, it will wait for 1800 seconds (30 mins).
Other possible reasons for this issue include:
1. Failed access to the storage repository location on the backup server.
2. Failed access to the backend database.
3. The return acknowledgment might be dropped due to a transient network problem.