System.IO.IOException: The specified network name is no longer available

That means windows is not able to access your network drive. There are a couple of things to note when using network drives in mcebuddy since the engine runs in kernel space by default:

  1. Enter credentials for your network drive in mcebuddy
  2. Check your network/server time, if the network time is off windows won’t connect
  3. Windows can’t access the drive

You don’t have fallback configured:

Fallback Destination → False

You can see more about it here: