VPN conflicts with email

Hello - I have been using AVG VPN for some time. I use Microsoft 365 Outlook for emails. A few days ago, with VPN on, I began to receive send/receive error message (0x800CCC1A). With VPN off, I receive emails, but they arrive late (eg,1 hour or more).
Does anyone know why there would be a link between VPN and Outlook?
I have not touched any settings.
Thank you from Montreal.