Encountered an unsolvable network problem and narrowly lost to almost seven engineers.
Encountered an unsolvable network problem and narrowly lost to almost seven engineers.
This problem has persisted for three weeks and thus far, we've managed to resolve it by speaking with four Network Engineers over the phone, two BT site engineers, and several Openreach staff from the UK's main fibre company—including a site engineer, senior engineer, and one of Openreach’s heads. Essentially, every technician who checked has confirmed the issue exists, yet none can pinpoint a solution. What exactly is this strange problem? 90% of websites function normally, and the internet remains operational. However, services like flights, hotels, Steam, Disney+, and even my solar energy system are frequently blocked. Some display odd errors, while most simply report that "the server at x website is unreachable." I've attached photos for reference. What steps have we taken to try fixing it? We replaced all Ethernet cables, reset the router, swapped out the router, double-checked every setting—including parent controls—and even tested the line back to exchanges, performed a full reset, applied signal boosts, and conducted every possible test. It seems every device connected to our network is affected. If you switch off the internet and use data, it works; connecting to another network does too. This is the most interesting part. Turning on a VPN usually helps a bit, sometimes improving access or resolving certain sites, but not all. If anyone has ideas or suggestions, I’d be grateful for your input. All the best, James
It seems like a DNS issue might be at play. I’d suggest manually configuring your DNS to one of the options @Oshino Shinobu suggested, enabling your VPN, and then clearing your DNS settings. If that resolves it, test without the VPN and finally with the default server. If it still works, likely something else fixed you already—just need to clear DNS across all devices.
It's best to address one task at a time so you understand the solution. Flush the DNS during these steps to avoid cached entries.
Did you clear your DNS after making changes? The issues you're encountering often stem from trying to reach a server in another region. Since this affects all devices, the problem likely lies with DNS behavior. This command is local only; it just removes cached data so you can test solutions and see if it helps. If DNS is involved, finding alternative servers that work will resolve the issue across devices once their TTLs expire.
They began working and I just looked at my phone—it came back. It doesn’t always stop working; it can be down for hours or even days. Irritating, especially right after I posted this, it seems to have resolved itself. I’ll need to save this post until it fails again, likely over the weekend, then try posting once more. Could you help me understand why you suspect DNS might be the issue? That way, when I connect my BT phone again, I can clarify what everyone thought. Thanks again!
Verify your connection status with CGNAT. If detected, it could indicate other users on the same provider have engaged in inappropriate behavior, causing temporary blocks for many within that ISP's network.