Hello,
It seems that you backup a remote Exchange server and the public folders and receive the error 'access denied' for the system logon account. Are you able to backup Exchange mailboxes and Information store? What is the version of Exchange on the remote server?
Try creating a new account with Exchange Administrator or Exchange Full Administrator rights. If the issue persists, revert with the exact error message that you get in the backup job log.
Regarding the second problem, we suggest you to post another thread so that it will be easier for us to manage different issues properly.
Note : If we do not receive your reply within two business days, this post would be marked ‘assumed answered’ and would be moved to ‘answered questions’ pool.
Regards.