Galaxy Grand 2 asks password for credential storage while trying to create a vpn
You have to use a pattern, PIN or password lock screen in order to configure and use VPNs. This is a limitation in Android which may seem stupid and annoying, but there are reasons for it:


The credentials storage has to be encrypted with a password, so that even if other apps are able to steal the files they would be useless.
VPNs are primarily used at corporations that allow employees to work from home. The servers on their network often contain sensitive information that could easily be compromised if someone would steal your phone and connect to the VPN.