OpenVPN disconnecting when locks in IOS client

[SipriusPT]

Hello,

I have an IOS 13.3.1 with OpenVPN installed, where it disconnects after some seconds when screen locks.

This IOS is not running any save battery mode, and OpenVPN is set to be running in background.

This VPN is through TCP.

Anyone knows what can be causing this?

Thanks in advance!

P.S. I know that its not related with pfSense.