How can I access the router from comand line, from LAN or Wlan? Thx

I did all these settings and I've started all 5 services+values in registry editor, but the error is the same. I've also tried with port forwarding but no chance. I need to use L2tp?Does anyone...

Why this thread https://community.tp-link.com/en/home/forum/topic/201614 doesn't appear in switches& routers submenu? If I click on it, it gave me page not found. Also submenu switches& routers...

I tried to setup a l2tp connection between a laptop and ER6020 remote router. I get the error 788 like in the picture.I added config here. Please tell me where I am wrong.Thank you