So this is my first time posting here, and I just started using the remote app on my android tablet.

I have tried scanning the qr code from my yacreader library on windows pc, and tried manually typing in the ip and port. However, after I have done everything, I try clicking in my library, but keep on getting the error: error connecting to server. Does anyone know the solution to this? If you do, please help me, thank you very much.

what operating system are you running YACReaderLibrary on? And what version of Android?

Check the firewall, if it is blocking the connection then the android app won't be able to connect. This is probably the most common cause for connection problems.

Make sure both devices are connected to the same WIFI. If they are, your router shouldn't be running any kind of isolation protection, devices need to be able to see each other in your network.