LOS Light Blinking Red? Here’s What It Means

What does the red LOS light mean?

LOS stands for Loss Of Signal. When the LOS light turns red or blinks red, it usually means your ONT or fiber router is not receiving the optical signal properly from the network.

In most cases, this is not just a normal WiFi issue. It usually points to a signal-side or line-side problem rather than a small in-home speed issue.

Common causes of LOS blinking red

The most common reasons include:

• Fiber line cut on the main route or last-mile cable
• Loose or disturbed fiber patch cord
• Damaged connector or excessive bend in the fiber
• Splitter or joint issue in the local line
• Upstream maintenance or area-side interruption

This is why LOS red is often different from issues like slow WiFi or buffering. For those broader problems, see our internet issues and solutions guide.

First checks you can do at home

Before raising a complaint, you can safely check a few things:

1. Check power properly

Make sure the ONT or router power adapter is firmly connected and the device is powered on. If you have separate ONT and router devices, both should be on.

2. Check the fiber patch cord gently

Look for a loose connector or any obvious disturbance. Do not bend the fiber sharply or pull it. If the connector looks slightly loose and you are comfortable, reseat it very gently.

3. Restart the ONT or router once

Turn the power off, wait about 20 seconds, then power it back on. Give it a few minutes to boot fully. If LOS remains red after that, the issue may not be something a reboot can solve.

4. Check if nearby users are affected too

If neighbors in your street, building or area have the same issue, that often points to an area-side line problem or route disturbance.

When does LOS need technician support?

If the LOS light stays red after the basic checks above, it often needs line-side verification or physical inspection. That can happen when:

• The line is cut somewhere outside the home
• A joint or splitter is affected
• The issue is not inside the router itself
• The signal has not returned after restart and cable checks

This is different from normal weak WiFi. If your issue is WiFi coverage rather than LOS, our router and mesh WiFi guide will be more relevant.

What information helps support faster?

If you are reporting a red LOS light, it helps to share:

• Your exact area or landmark
• A clear photo of the router or ONT lights
• Your registered mobile number if you are a Krishii Fiber customer
• Whether neighbors also have the same issue
• Whether the issue started suddenly or after cable movement

That helps support narrow down whether the problem is likely to be in-home, building-level or area-level.

Can restarting fix LOS red light?

Sometimes yes, but not always.

• If the problem was temporary, a restart may help
• If the signal is lost because of a line cut or disconnect, restarting will not restore it

That is why it is worth restarting once, but not repeatedly. If the status does not change, the problem is likely somewhere beyond the device boot cycle.

What LOS red is not

LOS red usually does not mean:

• Normal slow browsing
• Weak WiFi in one room only
• A minor speed drop

Those issues are usually different and are better explained in our broader troubleshooting guide and internet speed guide.

Important note for non-Krishii Fiber users

This guide can help anyone understand what a red LOS light means. But if you are using another provider, the actual line-side repair usually has to be done by your own ISP.

If you are not currently using Krishii Fiber and are only trying to understand the issue, use this page as a guide and contact your existing provider for restoration. If you are looking to switch later, you can still check our broadband plans.

Final takeaway

If the LOS light is blinking red, the simplest interpretation is: the fiber signal is not reaching your ONT or router properly.

• Check power first
• Check the fiber patch cord gently
• Restart once
• See if others nearby are affected
• If LOS stays red, it likely needs line-side attention

If you are an existing Krishii Fiber customer, sharing your area, registered mobile number and a photo of the device lights is usually the fastest next step.