Hello starratt,
I'm sorry to hear you're experiencing this issue. The recent 3.X updates have some major changes in the way the app is run which may be causing this issue in your specific case. Please send us a bug report the next time this happens by going to Help > Report a Problem so we can investigate your logs. Be sure to include a link to this forum post so we know it is you.
Once you've sent the report I'd recommend reverting to version 2.5.1 to see if the 3.X upgrade caused this behavior. You can grab 2.5.1 at
https://www.sighthound.com/account/ by clicking the "Looking for a previous version?" text.
Regards,
-Devin