Chaining Proxy and VPN in mac

[shayan73haghi]

Hi everyone,

Spotify is not accessible in my country, so I should use Proxy.
The problem happens when I am in university in which I should use VPN to connect to the Internet, in this case, I use Proxy for the Web by setting it in advanced setting of Vpn But in this situation, Spotify doesn't work.
I generally use Proxy in Spotify setting while I am using university VPN.
Two months ago it just works well but now it doesn't work.
I check firewall, proxy configuration, and everything is ok.
Beside Web-based Spotify works in this situation and My problem is with Desktop Mac version.