Are you using a username/password in order to connect your PC? Also, a few tips to ensure file sharing is enabled on your PC can be found here. How to quickly share files in Windows 10 - CNET
Sounds a little like what I am experiencing… A sort of work around is to have it scan the library until it finally finds everything, end before accessing new files to open an already existing item. I have no idea why but when you start playing a file it will connect and keep the connection. After a second you quit and play the item you want to see…(Provided it will find something eventually)