SoftEther VPN User Forum

Hello,
I'm using SE since many years for remote connection to sites (PC to LAN) for remote support. Now I experience a strange behaviour: some connections I've registered in SE Client are perfectly working on my laptop, but not on my PC (error code 1), even if connection settings are the same (export from the working laptop to the PC) and both laptop and PC are in the same LAN.
I've reinstalled SE Client, recreated virtual adapters, recreated the VPN connection, but nothing changed (and other VPN connections are working on the PC). What can I do?

Thanks!

That PC (error code 1), had it worked OK on all SE servers in the past?

- is there a log entry on the server when the client fails with error code 1?
- are you connecting via VPN Azure, DDNS, direct IP or domain-based server host name?
- are you using NAT-T, proxy server or a server certificate?

When the PC shows error code 1, please try to telnet from it to the failed server's addr/port.
Check How do I know if a TCP port is open or closed?
So, while SE client quits with error code 1, telnet...

If the port is open, only a cursor will show.
If the port is closed, a message will say Connect failed.

To be clear, we know already that the server's port is open because your laptop works fine, but here we are testing the PC's alternative connect method.

solo wrote: ↑

Wed Mar 02, 2022 5:18 am

That PC (error code 1), had it worked OK on all SE servers in the past?

Yes

- is there a log entry on the server when the client fails with error code 1?

No log entry

- are you connecting via VPN Azure, DDNS, direct IP or domain-based server host name?

I'm using softether.net DDNS, trying with all ports available (443,992,5555,1194). On the laptop I'm using the same DDNS with port 5555

- are you using NAT-T, proxy server or a server certificate?

NAT-T

When the PC shows error code 1, please try to telnet from it to the failed server's addr/port.

Telnet connecton to DDNS address and port 5555 fails.

Before open this thread I've checked that windows firewall allows SE Client and everything seems ok.

This time please completely disable the firewall and re-test it.

If still error 1, on the client's LAN run NAT Test Page - what NAT type is there?

Get PortQry and on the error 1 PC, run: - is it LISTENING or NOT LISTENING?

Also is this OK?