Sometimes, it can be little frustrating especially if its working fine in another environment. Just wondering if it could be due to 'port/firewall' issue between plug-in and storage? We are not snapping sql yet with SC but we will soon, hence this thread is very useful.
There is another thread here, I believe could be relative.
https://community.netapp.com/t5/Data-Backup-and-Recovery-Discussions/SnapCenter-4-0-No-storage-connection-is-set-for-StorageSystem-lt-Fully-Qualified/td-p/140195
Quick Start Guide For SnapCenter Plug-in for Microsoft SQL Server
https://library.netapp.com/ecm/ecm_download_file/ECMLP2861721