Device gone from map

Hello, from yesterday my device went missing from demo server. When I added it again it won't connect again to server and it is not on the map.
My friend also has this problem on demo server.
Can you help us?

We clear the database periodically. That probably explains why it disappeared, but once you add it again, it should work.

How often do you clear database?

There's no predefined schedule.

Is there a way to make exception from clearing database?

You can sign up for one of the subscriptions:

https://www.traccar.org/pricing/