There’s a few things to check in regards to WiFi and your device, @Fr0van . Take a look at some of our WiFi examples, here & here 
For most of our Security Cams, we reccommend a minimum upload speed of 1Mbps, but 2 Mbps is recommended for optimal performance.
Also, take into consideration the distance from your router to your device as well as any objects that may cause WiFi interference. Let us know if we can help in more detail!