Routers are our gateway to the Internet.Its stability is key when it comes to being able to enjoy a good connection quality on a daily basis.However, there are times when problems arise in them that can leave us offline for a long time, and for that the red LED light is usually used.On most carriers' fiber routers, having a red LED light appear on the router all of a sudden is not a good thing.If we have run out of Internet connection, this light will appear in the one corresponding to the status of our fiber optic connection.For example, in the Movistar Smart WiFi router, we find four LED lights.The one on the far right is the one that indicates the status of our Internet connection.If it is solid blue and not flashing, it means that we have an Internet connection and everything works correctly.The network activity indicators are on the back if we have an Ethernet cable connected.However, if the LED is solid red, then we have a network problem.The red light indicates that the Internet connection could not be established, either due to our problem or due to an operator problem.In the event that the problem is ours, the fiber optic cable may have broken or is in poor condition.If it's the carrier's fault, then there's not much we can do to fix it other than wait for the carrier to fix it.The red light can also be found in other router LEDs in Movistar.For example, if the red LED is for the phone and it flashes, it indicates that there is an issue with the phone.If it is fixed, it indicates that the telephone service cannot be accessed.In the rest of the operators, the use of the red light may change.In the case of Orange, there are no red lights, instead white color codes are used.If the light flashes white fast on the Livebox 6, the fiber is not connected.If the light is solid white or slow flashing white, then the fiber may be connected, but the Internet password is not entered or there is no Internet connection.At Digi, however, we have a similar behavior depending on the router, where the red LED indicates that there is a problem with the connection and the Internet is not working.In short, the lights are a very important way that the router has to communicate to us that there is a problem in our fiber optic connection.Going to the manual is the most recommended option, but if our router is in place and we have not touched the cables at all, it is most likely that the problem is a matter of the operator, and we will have to wait a while for it to be fixed, or restart the router to see if that fixes it.