Just to help manage your expectations, this is a community forum. Everyone who participates here whether that be NetApp employees, partners or customers do so purely on a volunteer basis.
The challenge here is you are running a legacy version of ONTAP which is 100% now unsupported. If you have other NetApp systems that do have active entitlement, then I would suggest searching the knowledgebase for some relevant articles that might at least point you in the right direction on what to check.
Potentially the services that handle ssh/gui access have experienced an issue, in some cases doing a takeover/giveback might be helpful along with a reboot of the impacted node.
You can also consider accessing the impacted node's service processor and looking there to understand the impacted nodes status.
Hopefully this helps point you in the right direction.