Try to use low graphical settings.
- Open LotAtc client
- Go to the options
- In general tab set the following options

Restart LotAtc client.
You run DCS in window mode within LotAtc client ?
Your DCS is in window mode and currently displaying 3D view (plane, cockpit….). Open the map in DCS will solve the problems. There is a conflict somewhere in directX between DCS and LotAtc.