Hi,

At first, I thought the issue was with my ISP, but after testing further, I believe the problem is related to my Deco device.

I have a fiber optic connection that terminates at an ONU (as the ISP calls it). A PPPoE connection must be configured to access the internet.

When I set up the PPPoE connection directly on my laptop, I get download speeds of 400 Mbps or more, which is fine.

However, when I configure PPPoE on the Deco, the connection works but the speeds are very low and behave strangely.

On two laptops connected via WiFi, download speeds are only 20–30 Mbps or a little bit more, while upload is around 80 Mbps (which matches my contract and has never been an issue).

When I test with a Samsung phone over WiFi,  and on both laptops using WIFI, they get low speed.

When tested with the ethernet cables connected to the Deco, speed is above 400mbit. I optimised the network from the app but still nothing.

Could it be a faulty WIFI module on Deco or Firmwarebug something else?

I contacted the ISP, and they confirmed there are no issues on their side and suggested checking my equipment, which makes sense.

What could be causing this?