So the initial problem is that your android tablet cannot discover your Windows 10 computer, right?
Do you maybe have VPN (Virtual Private Network) active?
Do you have any third party firewall software that might probably blocking the spacedesk connection?
If yes, please make sure to add c:\Windows\system32\spacedeskService.exe on your exception list to allow incoming/outgoing connection.
For assistance, please also check Troubleshooting – Network Connection chapter in our user manual.