AutoSupport is not delivering after ONTAP upgrade

• Testing connectivity from the command line:

::> autosupport check show-details
Node: Node_name

Category: http-https
          Component: http-put-destination
             Status: failed
             Detail: HTTP/S PUT connectivity check failed for destination:
                     https://support.netapp.com/put/AsupPut/. Error: Could
                     not resolve host - 'support.netapp.com'
  Corrective Action: Use "dns check" command to check DNS connection

• DNS status is down:

::> dns check -vserver xxx
                              Name Server
Vserver       Name Server     Status       Status Details
------------- --------------- ------------ --------------------------
xxx         1.2.3.4         down         Operation timed out.
xxx         1.2.3.4         down         Operation timed out.
2 entries were displayed.

• Managment and Intercluster LIF's are on same subnet:

::> route show-lifs

Vserver: cl-Tu
Destination             Gateway                 Logical Interfaces
----------------------  ----------------------  ------------------------------
0.0.0.0/0               1.2.4.5                 Node01_icl,
                                                Node01_mgmt,
                                                Node02_icl,
                                                Node02_mgmt, cluster_mgmt