We need a little more detail to assist you. What device is your music library stored on? Have you been able to connect to your music library in the Sonos app before?

What library? Where is it stored? What Sonos OS are you running? Which version of the controller do you have?

Have you called Sonos Support directly to discuss it?

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

Pretty much any tidbit of information might help us help you.