Recurring stopped working

We have Salers Orders which are marked with “Is recurring”. They have worked for a long time, but we noticed recently that it has stopped.
Recurring is quarterly with a From and To date. We have not set an End date.

Is there a log related to this, where we can see why it has stopped?
We are self-hosting and using version 4.

This seems to be working fine in the latest version.
You can check error log list or console error if any.

Where can I find the error log? Im running it on Ubuntu Server 14.04