you may want exchange auto reply all received message but not the OOF. And you won’t like keep outlook open for such function. There is an server side rule for this issue.
1- connect your mailbox through MAPI
2- create an outlook rule
edit subject and the message body.
6-check this rule on owa
how is it going:
Notice: you must enable the target domain autorelpy function on organization node of emc first.