If you have an IP Address with letters, then you probably have an IP V6 address.
To connect spacedesk you need an IP v4 address.
Run “ipconfig” on your Windows machine and see if there is any network adapter with IP v4 Address.
Or use spacedesk Driver Console on your Windows machine to find network interfaces and their IP v4 Address.
Please also check instruction manual (especially the paragraph below): https://manual.spacedesk.net/NetworkDiscovery.html