Change the router's WiFi 2.4GHz channel.
Be sure the channel is from 1 to 11.
I have the Dlink DIR-826L router and I am having issues with speed when connected to a specific mobile device.
I have the router running wired to my PC and wireless to my PS4 and both connections get great speed, around 25mbps as it should be.
However when I try to connect it to my mobile phone the speeds I get are pretty useless, often less than 1mbps. But sometimes it will get 25 for a short time, and it often fluctuates a lot during the speedtest. It's generally to useless to watch a vid on youtube for example without a lot of continual buffering at 480p.
My phone is a Samsung J7 neo which is fairly basic. But it connects fine to other wifi, for example at work I have no problems. as far as I can tell it does not support 5Ghz and only 2.4Ghz as I only see that network. Friends seem to be able to connect to my wifi just fine with their phones. The connection strength is always full, just the speeds I get on that device are mostly useless.
Any ideas what could be causing this? I assume it is router related as the phone is fine on other wifi networks.
Thanks in advance for any help.