@canscot if you are connected directly to the cable line and already did a reset and still have the problem try this, from your main cable line connect the splitter you got then connect the modem to the splitter and try the test again. Sometimes if the signal is too high it would cause problems.
it happens on wifi
i did a ookla speed test and it is 7.54 up to 10.61 download speed .i'm paying for 30.0 download
Welcome to the community!
If it's just happening on Wifi, have you verified you're not getting interference from other networks? I previously posted some information regarding possible causes of interference here.
Do any of your devices support the 5Ghz network? If so, have you tried that network?
You should note Wifi speed tests will generally be slower than wired speed tests. Additionally, did you perform your speed tests using different hosts? The speeds can vary drastically between the different hosts.
You noted in a later post that it also happens with ethernet cable. What happens? The fluctuation and stopping? Or slow speeds?
Hope this helps