When editing the Backup Configuration, if you click 'Save' without entering the passphrase, the following error is displayed, and the changes cannot be saved.
"No passphrase specified. Not allowed to reuse passphrase as no passphrase exists in system for fileserver URL {0}."
VMware NSX-T Data Center
VMware NSX
There is no "red asterisk" for passphrase input field notifying user that it is mandatory field. Backup Configuration window shows option to "SAVE" even though inputs for passphrase field are not entered.
This issue is resolved in VMware NSX 4.1.1
Workaround:
Follow the UI error message and input the passphrase to save the settings.