Hello,
https://veepn.com/vpn-apps/vpn-for-ios// through this link you will know about the Word hangs when using VPN to connect to the network. The workaround is to change the settings in Word so that you can use it while connected to the VPN.
1. Click Tools and then click Word Options.
2. Click Connections in the left pane, and then select Use a proxy server for my Internet connection.
3. In Local area connection, click More Settings, and then select Use a proxy server for remote connectivity if you are going to access a remote network.
4. After your changes are completed, close Word.