Clear Blue advance digital ovulation test

I have bought a clear blue events digital ovulation test the 20 test pack and I've been using the monitor for about 1-2 months without any issues and now this month which is my third month of using it I received a arrow pointing to a book symbol on the display and it's been there for about 2 days.

I don't know what to do or what this means or how I can reset the monitor.?

If clear blue can send me another test kit that will be great.