I/O Error
This sometimes is shown in place of No authorization to access host errors. Use the same methods for resolving this issue. It is also seen when the secure files on each host are different. You may also want to try restarting the agent.
No authorization to access host
Probably the most common error, this is caused by a mismatch in the ACLs on the remote host and the credentials you are using to connect to the remote host. The files you will want to verify are the users or users.local files on thetarget, although the exports file may cause the error also. Generally, commenting the nouser entry will temporarily solve this, but is not recommended. Refer to the rscd.log in the agent install directory of the remote host to validatethe user trying to establish the connection vs. the entries listed in the ACLs on that server.