Whenever the router's DNS server cannot resolve a domain name by going up the hierarchical DNS tree, it puts an entry to this effect in the system log. There is a bug in recent firmware where the severity of these messages has been set wrong (they should be set to informational). This means they cannot be filtered out in the UI.
Slow speed, intermittent dropouts, breaks in the signal or no signal on some or all devices or no internet access might be caused by Wi-Fi interference from other local networks, which can also lead to a permanent reduction in speed. No ISP can be responsible for your local environment, this is mainly a byproduct of the popularity of Wi-Fi.
Generally speaking, the 2.4GHz band suffers much more from interference than the 5GHz band, but the 2.4GHz one can sometimes have a better range, but this all depends on your local area.
Have you had TalkTalk’s Wi-Fi optimisation disabled on your Sagemcom FAST5364 router? When this is enabled, as it is by default, it has the power to override any Wi-Fi configuration changes that I might suggest that you need to make. This will not help rectify this type of problem if Wi-Fi Optimisation is allowed to change my suggested settings. Only TalkTalk can do this for you, you cannot do it yourself. If not, just request they disable this for you in your reply.
The next stage involves sending out a guide to you to help you get me some important diagnostic results so that I can analyse them for you and recommend changes to your router configuration to solve them.
I only send this out to people who request it.
