Hello,

In regards to backing up the VSAN, are you really trying to backup a VSAN or instead the startup configuration on the switch? If you are trying to copy the configuration via Device Manager through Admin / Copy Configuration, the error message indicates that you don't have a tftp / ftp / etc. server running or you can't connect through it. Please note that DM doesn't use the built in tftp server that FM uses for other purposes. You need to manually install and start the tftp server prior to running this.

If you are trying to backup just a VSAN, please provide how you are trying to do it. Thank you.