I run a small business, we have our own domain and a hosted email service.
Recently one of our employees who works from home and uses Virgin Broadband as her ISP has started having email she sends from her business email flagged up as unsafe by Gmail (and potentially others I suspect). She uses Outlook email client and has her business email (so not a virginmedia email account) correctly configured with our mail server settings.
Every business email she sends is being flagged by Gmail as being unsafe. To help troubleshoot I had her use her mobile phone as a hotspot and send test email. Email sent this way Gmail does not flag as unsafe. So I'm pretty sure the problem only occurs when she is connected to the internet using her virgin broadband.
I have had a look at the SMTP header info from email Gmail considers unsafe (extract below) and the issues seems to be with spf and google not liking the virgin I.P address. (I've obfuscated part of the I.P address and our business domain name for security - but an I.P lookup suggests this is a Virgin media I.P address.)
spf=softfail (google.com: domain of transitioning firstname.lastname@example.org does not designate 77.100.116.xxx as permitted sender) email@example.com
Received-SPF: softfail (google.com: domain of transitioning firstname.lastname@example.org does not designate 77.100.116.xxx as permitted sender) client-ip=77.100.116.xxx;
Is there anyway that these outbound emails are being routed by a virgin media email server instead of ours?
I'm at a loss as to how to troubleshoot this further and any help would be appreciated.
Just to recap
Sender is email@example.com
Outlook email client (on Windows - not sure what version OS)
Outlook account settings correctly configured for my business.co.uk smpt server (inbound and outbound).
GMail flags the messages as potentially unsafe
Problem does not occur if the sender disconnects from virgin broadband and sends using another ISP for example mobile data.