I use 4G connection through my phone as my main internet connection. The problem started today.
I have called my operator's technical support, and they confirmed that the mast I'm currently connected is working as intended. There are malfunctioning masts in the city i live in, but they are in such distange away that they shouldn't affect me. Signal strength is decent on my phone too(I'm using Mobile signal application to measure it)
I set cmd to continuously ping 220.127.116.11 and it seems that if I disconnect and reconnect my phone to pc, network connection works normally for few minutes, then it starts to slowdown. The ping to 18.104.22.168 for example drops from about 50 to 800-2000 and download speed on speedtest barely reaches 1mb/s when its normally about 10-20.
Only abnormal thing to happen to my phone recently is mini usb socket getting a little sand in it. I have cleaned it thoroughly using pressurized air, though I plugged it in one or two times while still had some in it(thats how I noticed it in the first place). There is no visible damage in the microUSB and I can't spot anything wrong in the socket either. Besides, I did speedtest on my computer and the phone itself and both got same results, so I don't think there is a problem with the cable (couldn't test the cable anyway, since I have only one) or the socket. According to techsupport guy I called to, my connection speed was normal about 1500, after which it dropped the connection for a moment or something.
-I have restarted my phone completely by removing the battery and sim.
-I have scanned my phone for malware and found nothing
-I have the most recent updates