Have you moved the speaker? Try to place it close to the router. As wifi networks can be affected by other networks, your network performance may change if, for example, your neighbors have new routers or other devices which affect your router's performance.
The performance of your Pantheone I wifi / multi-room speaker is dependant on the performance of your wifi network. By its nature, wireless LAN may experience interference depending on environmental conditions. Depending on the wireless router used, some network operations may perform differently.