Hi,
if you can't connect from your iDevice, that shows that something is blocking the connection;
The first thing to check is that you are definitely connecting to the same local network as your PC/Mac. Make sure that your iDevice is connected to your home network wifi, and not your neighbour's wifi, or your wifi guest network. The best thing is to check the wifi name in the system settings app.
This article runs through various things to check (such as wifi extenders)
If that doesn't help, then the next step is to try rebooting your wifi router. It is annoying - but a lot of modern routers are surprisingly unreliable.
if that doesn't help, then the issue is most likely a firewall or anti-virus app.
The best test of this is to completely disable your firewall and anti-virus app, and reboot your computer (this step is important).
Then test again. If you can connect now - you know the culprits. You can enable the security apps one by one and tweak as needed.
couple of additional points to note:
1) while you turn these apps off, you might want to disconnect your router from the internet. That should keep you safe.
2) for an easy life, here are my tips on security apps:
hope that helps,