@pgonline Hello, 

May I know the network topology or network map in your home: 

For example : ISP ----- Wi-Fi router ------wired powerline adapter   ___________ wireless extender )))((Windows 10 PC.

Is there any switch or range extender between powerline adapter and router? 

May I know which VPN software you are using to connect to that VPN Server,if possible， please share us a photo of the Error message.

What is your current firmware version of WPA4220 V4? 

@Solla-topee Hi

I have the tp-link connected to my ISP Router by cable and connect the laptot on the other tp-link module by cable or by Wi-Fi, have the same problem

I do not have a range extender, only ISP router and the TP-Link power line

The tp-link have the last firmware TL-WPA4220(EU)_V4_210222

I user the open vpn client to connect to a open vpn server on a Synology NAS

The error is wrong credentials (the credentials are saved and if I connect to the ISP router by cable or by Wi-Fi, or any other Wi-Fi network the VPN connects immediately)

@pgonline Hi, 

Thanks a lot for your reply! As this case is little special, we'd like to follow up your via email, please check your inbox for email subject "【Forum ID 257704】"  thank you.