Automatic Page Refresh stops refreshing after some time

Hi,

we face the problem that some Dashboards that were using the Automatic Page Refresh in our environment are now facing some issues from time to time:

The dashboard (located in shopfloor) was used to update each time when the source got any updates. After some time now, the refresh just stops, although the source is changing on and on. 

To solve it, it is necessary to manually click on "Refresh" once or to re-open the dashboard.

Then it again takes a while (10 minutes to 1 hour) until the problem appears again.

Anybod having experience with this?

Thanks

Johann