It is most likely something to do with your internet connection. You don't say what hardware you are using. Are you streaming with cell phone data on an iPhone? Through a DSL router? Cable modem?
I listen to KALW with the NPR app on my iPad with no interruptions. We have a fast cable internet service. I stream some other programs on my iPhone while walking the dog with mostly good service.
We listen to iTunes radio over WiFi at dinner. It mostly works well. Somedays it pauses for a few seconds.
The simplest thing to try is to restart everything; routers, modems, computers.
Check the WiFi signal strength. Maybe the router got moved, fell over or someone put a metal object over it or near it blocking the signal.