The fix:
-go to iManager ( ip>/imanager.html)
-go to NBM VPN Server Configuration
-click the server
-in the 'server certificate' section, choose a different certificate (use the search icon to find a different one)
-go to iManager ( ip>/imanager.html)
-go to NBM VPN Server Configuration
-click the server
-in the 'server certificate' section, choose a different certificate (use the search icon to find a different one)