Which is the IP address that you are adding. 7.x supports only c-mode systems and the IP used to add to the storage systems should either be a Cluster Management LIF or a SVM management LIF.
Could you do a "net int show" on your storage system and use the the mgmt IP that shows as part of the output.
If it doesnt solve the issue, paste the net int show o/p here and also check if you are able to ssh to the system using the same IPs.
Thanks