APM: After "Fly to" frozen for a second


APM Copter, 3.2.1 firmware and MP 1.3.25, telemetry link on 900MHz.
MP works fine. Problem is only with maps. Despite wifi good connection when i zoom sat map the map is blur, can’t download proper map data
But the bigest problem is with “fly to”. I tried it on 2 good PCs. When i click “fly to” transmittion between model and MP froze for few second (map not moving, digits on left not changing) and nothing happened. On second computer sometimes “fly to” works sometimes no - often no.
Can’t find any info in web. Ask for advice