@Mohamad_Oday
Hello, as per the log you attached, it seems that the PPPoE connection is disconnecting, we would like to confirm some basic info then we can take further steps to fix it:
1. Who is your ISP? Ensure the cable between the WR840N and the modem is good, or try with another cat5e or cat6 cable and confirm.
2. If step 1 still doesn't help, please check the connection by simply connecting your main computer to the ISP modem directly, then dial up on the computer as below, ensure you get a stable connection without any dropouts:
https://www.tp-link.com/support/faq/921/
3. If the ISP modem connection is stable when tested in the step 2, please then connect the ISP modem back to the WR840N, and reconfigure it to connect to the internet. Kindly confirm how would the connection recover after it disconnects, do you need to re-build the WAN connection or just restart the WR840N?
Thanks a lot.