As of Zerto Virtual Replication version 2.0 Update 4 (Zebra), communications between the Zerto Virtual Replication GUI in the vSphere Client and the VM running the Zerto Virtual Manager (ZVM) are executed via an SSL connection. After upgrading to 2.0 Update 4 (Zebra), an administrator will note that the Zerto Virtual Replication GUI may not be properly available.
2.0 Update 4 (Zebra)
In order to restore the Zerto Virtual Replication GUI in this situation, the administrator must clear the IE cache, and re-open the vSphere Client. To do so, follow the instructions in the Microsoft KB article "How to Delete the Contents of the Temporary Internet Files Folder".