What is happening is a VPN client app is attempting to communicate to a VPN server service over the Internet and is unable to. Either because the iPad is not connected to the Internet or there is something restricting it from creating the VPN connection.
At some point, a VPN client was installed on this iPad. VPN is a means to create a secure "tunnel" between the iPad and a VPN service over the Internet. These are commonly used for business transactions where sensitive information is involved.
Is this your personal iPad or was it provided to you by your company or school? If the latter, you will need to contact their respectie IT department for assistance.
If it is yours, did you install a VPN client? If so, just delete it.