Hi, I had the same problem as yours before. Based on what you said the problems that you have only happens with wireless devices that you are using. I highly suggest you to go to the modems page which is usually 188.8.131.52 access it using admin as a usernam and password. Look for basic > WLAN and change your 11N Band Width to 20MHz and channel to 11. Submit it and also run a speed test after to compare it with what you usually get.
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