You have configured Virtual IP address for NSX Advanced Load Balancer.
The UI only provide function to edit the VIP but not remove.
Environment
VMware NSX-T Data Center 3.x VMware NSX 4.x
Resolution
Deleting Advanced Load Balancer VIP is not supported, this IP address can only be edited.
If you need to delete the ALB VIP IP address, please open a new case with Broadcom Support, ref. Creating and managing Broadcom support cases, with a reference to this KB article.