Check hosts file at the client side to se if there's any restriction there.
Also, run a save from the client side to see if you find the same error, the command could be like:

save -v -s -b /tmp

Also check on the client the /nsr/res/servers file, if there is one delete it and restart the services and retry the operation

regards
Abdon

This usually happens with older NW releases (haven't see that with newer, but it could be there) when NW can't connect to nsrexecd on remote system and instead rsh will be tried. Since for years all r* commands have been banned by admins you get message as you see.

The core issue in your case is that server can't communicate with AIX client - now you must run few tests to figure out why.