Streaming Audio Stops When iPhone AutoLocks

I often listen to streaming audio on my iPhone via YouTube or other web services, but starting several days ago the audio is interrupted each time my AutoLock kicks in after 2 minutes. This is very frustrating and I don't know why this problem suddenly arose. This happened once before for several weeks a couple of years ago and mysteriously stopped. Please don't tell me to disable the AutoLock feature, as I want the screen to automatically lock after a minute or two; I just don't want ongoing streams to stop mid-play when that happens. Thanks.