Hi @BeyhanDerya 

May I know what is the status of its network light when VR600 loses network? Can the range extender still work at this time?

Please check what IP address the client obtains at this time? Refer to the following instructions:

How to find IP address on your devices

Please try to see if you can ping the modem normally at this time?

How to Use the Ping Command

Typically, the modem's IP address is 192.168.1.1

When experiencing an unstable Internet connection or Internet dropouts with a TP-Link DSL modem router, please check the DSL light status and follow the suggestions below:

If the DSL LED goes off when the problem occurs, please review the following troubleshooting steps:

    1. Contact your Internet service provider to confirm that the connection is stable.

    2. Try using another DSL cable to connect the modem router to the DSL jack.

    3. Reset the modem router by pressing and holding the Reset button.

If the DSL LED is on, but the wireless connection is unstable, please review the following troubleshooting steps:

    1. Check whether the wireless connection will be automatically restored. Check the Wi-Fi LED on the router when it happens and see If the wireless network can be found via your end devices.

    2. Change the wireless channel, channel width, or get away from a wireless interference source, such as a microwave oven, etc.

If the DSL LED is on but both the wired and wireless connections are unstable, please review the following troubleshooting steps:

    1. Contact your Internet service provider to confirm that the connection is stable.

    2. Log in to the web management interface of the modem, get a screenshot of DSL Status page, and save the system log.

    3. Contact our support with the information above for further help and tell us who your internet service provider is.