Hi,
Which ONTAP you are using?
I am assuming you are on 7-mode:
For GUI:
Have attached the screenshot.
Or,
You can also do it via command Line:
fiiler> options autosupport (This will list all autosupport options, the one you need is given below)
autosupport.mailhost mail-host.abc.co.uk (Do it for HA Parter as well)
In case it is cDOT, then you may use this command:
For cDOT:
::> system node autosupport modify -node <node> -state enable -mail-hosts mail-host.abc.co.uk -from alerts@node.example.com -to support@abc.co.uk
Thanks!