Outgoing Emails with Attachments Dropped

[curglaff]

Hi everyone! Whenever I try to send emails via Outlook with anything resembling a small attachment, the email doesn't leave the Outbox and fails to send.

It seemed like a fragmentation issue (and based on a similar topic) I tried setting the LAN interface MTU to 1492 (as it is in the router and from testing) and the MSS blank/1452. No luck sadly.

The setup is pretty simple: PC > OPNsense VM > Modem Router > Web.

Any ideas?

[mimugmail]

Try MSS 1300 if its fragmentation

[curglaff]

Thanks for the reply mimugmail, no dice I'm afraid. I'm wondering if there is something wrong in the interface setup that could be causing this...

Could this be caused from the IPv4 Configuration Type on the WAN interface? I'm testing different combos to see if it will work. Apart from that, everything else (web proxy, IDS, FW, AV) works perfectly.