Email sending blocked with the VPN
Your email client can't send messages when the VPN is on? It's an SMTP setting to tweak — and once it's done, it works VPN or no VPN.
Why it stops working
When the VPN is on, monVPN replaces your IP address. Your ISP's SMTP server therefore no longer recognises your IP and refuses the send.
monVPN also blocks SMTP port 25 outbound on our servers to prevent any SPAM from leaving our network.
Switch to authenticated SMTP
In your mail client (Outlook, Apple Mail, Thunderbird…), change the outgoing SMTP server settings :
587 SSL
Authenticated submission. Most common option.
465 SSL
SMTPS — historic variant, also accepted.
Use your ISP's SMTP server with your mail credentials (login + password). Bonus : authenticated SMTP works whether you're connected to the VPN or not.