Can't connect to any servers when using a VPN

[weekender]

Tried on my guild's server and my own. As soon as I try to connect, boom,

Server connection failed: The remote host closed the connection.

It's so fast that it seems Mumble doesn't even try to connect.

Looking at the console log, all it says is:

<W>2015-05-11 18:14:49.965 OpenSSL Support: 1 (OpenSSL 1.0.1m 19 Mar 2015)
<W>2015-05-11 18:14:49.971 SSL: CA certificate filter applied. Filtered size: 94, original size: 94
<W>2015-05-11 18:14:49.974 ServerHandler: QOS2 loaded

I can connect to both server no problem without the VPN.

Is there a specific setting to change on the server side? I have my own server running murmur on it so I can easily change the ini file.

I made some searches online and saw something about "loopback" not being enabled by ISPs. Is that the culprit?

Using Mumble 1.3.0 client (Win 8.1 64bit) connecting to 1.2.8 murmur servers.

[kissaki]

There is no special setting like that.

Not sure what you mean with 'loopback'.

[weekender]

My VPN is the culprit so I'll check with them, thanks.

[mkrautz]

Weekender, you could also try disabling QoS in the Mumble network settings. That setting has been known to break on VPNs before.