SAN Storage discovery fails in Secure Connect Gateway

Hi All - Will need your help on an issue I am stuck at the moment.

We have one "SAN Storage [Model: ME4024], which was discovered in the SCG couple of days back. After I triggered all device re-discovery we see this SAN device has changed its status from "Success" to now "Failed" in Devices dashboard. Not sure what went wrong which lead to this issue.

Following are few troubleshooting steps performed:

1. Restarted the SCG virtual appliance and then tried discovering twice but it failed with below errors.
     Error:

2. Then thought removing the Account credential from Credential Profile, delete the Account Credential for Storage device type and re-create it and see, but I was unable to remove the checkbox for Account credential from Credential profile with following error,

Still I tried deleting the Account Credential and could see error there too as follows..

3. I also checked the Support assist option whether is checked at Storage Management console and found it's checked too.

4. Tested the PING test from SCG appliance PUTTY session to Storage Management console IP and the PING test succeeds.

Kindly help in this regards on what could have gone wrong that this SAN device is non-discoverable all of a sudden.