v2rayN, v2rayNG and v2flyNG are graphical clients in the Project V ecosystem. The interface imports, selects and manages configurations; the underlying core handles the connection. v2rayNG uses the Xray core, while v2flyNG uses the V2Fly core. Even when the protocol name is the same, specific extension fields, transport combinations and security parameters may not work identically across both cores.
If a share link imports but the connection fails, first check the protocol, server address, port and security settings, then review the specific error in the logs. Reinstalling a different package won't fix an underlying configuration issue. To understand how VMess, VLESS, Trojan and REALITY fit together, read the protocol and core technical handbook before deciding whether to switch clients.
Keep your first test simple: start with a known-good configuration and the default routing mode. Confirm that your browser connects as expected, then enable per-app proxy rules, custom DNS or other advanced features one at a time so you can easily undo changes. If only terminal tools can't connect, check their proxy environment separately rather than assuming the client installation failed.