Change the IP address and Cluster Interface assigned IP address back to the original address.
If you are unsure what that address was, go to https://current_sps_address:8649/api/authenticate. This should cause the browser to throw an untrusted SSL certificate warning. At that point view the SSL certificate in the browser. To see the original IP address, look at the Subject Alternative Name in the certificate.
An example from Chrome below:
Then change the SPS IP address back to the one listed in the certificate SAN. Then disable the Cluster Interface and commit the change. Then re-enable the Cluster Interface and assign the original IP address to the interface and commit the change.