@heyigun Not looking good tbh and I can't really help properly from a distance so to speak, however I will leave you two more suggestions to try or these would be my next attempts anyway, 1 Factory...

@heyigun In that case you'll need to badger Kevin or Stella for a fix it FW, I can't think of any other reason why it won't accept it other than you now have basically two conflicting instruction...

@Sandymerson First thing to check is that your connection is stable, you can see this in the router page - Advanced -> Status, you want to be able to see figures that approach the isp speed you have...

@Sandymerson If you haven't already start by updating the router to this if you are in the UK https://www.tp-link.com/uk/support/download/archer-vr2800/#Firmware Not that this will be the issue...

@Sandymerson Whats the exact issue you're having?

@Kirollos_Samir I can't see anything blindingly obvious from that, all I will suggest is that you check your IP address is correct i.e the one that starts with 45 and that the Gateway one 172 is also...