Why can't TNAS PC application search TNAS device?

Reason 1: TNAS device is not within the same network as the computer. Please make sure TNAS is in the same network as the computer.
Reason 2: Firewall has been enabled on the computer. Please close the firewall and try again.
Reason 3: Two or more network cards may be in use. Please use only one and disable the other ones.
Reason 4: A system file exists in the hard disk which led to failure of the normal start of TNAS. Please pull out all hard disks, insert them again two minutes after rebooting TNAS, and try again.
Reason 5: A VPN service is enabled in your computer. Please disable VPN service and try again.