Problem with worlds freezing

I have timers set up on my worlds and this hasn't been an issue in the past. Now, despite the timers, my worlds are idling out and I get no notice till I try to post. Then I always have to reconnect.

Any idea what is causing this or how I can fix it. This seems a new occurance and my internet connection is stable, far as I can tell.

There are so many possible causes for what you're experiencing that it would take hours just to test all of them if we were actually at your computer and very few have anything to do with MC. If your timers are firing properly, my first suspects would be your router timing out the connections or brief periods of very high latency causing the mud to believe you've disconnected.