PROXY conflicto

[Help Group]

I have configured the Proxy (not transparent) but the computers connect to a VPN (correctly) to use an organization's system, but during use it gives a connection error, the connection is rejected.
A test that they carry out is to open a website from the corresponding IP and it should show "ok" on the screen, but it does not and indicates a proxy error; You do the same without the proxy and it connects without problems.

VPN network: 172.27.0.0

Ip that should arrive and gives error with PROXY: 10.30.200.238