But to look into it I need the full details. This post from 7.11.11 is not where I'll go into this area.
Please start your own new post where we can chat about the router make, model, settings, firmware version and more. I know it's asking a lot but it's technical so we'll have to be able to look at the WiFi channel and more details. Some owners can't do that so for those we have to let your tech support visit the location.