My job uses Outlook Webmail, so I've set it up (from a VM, since some settings are hidden outside MSIE) to redirect all mail to my Gmail address.
However, Gmail is not fooled, and adds 'Spam::' to all subjects in the redirected emails. Filtering the emails with 'never send to spam' has no effect on that.
The headers seem to imply that the issue arises because my job's SMTP server is not vetted by Google as a legitimate SMTP sender:
Received-SPF: softfail (google.com: domain of transitioning [some test email] does not designate [my job's server address] as permitted sender) client-ip=[my job's server address]; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning [some test email] does not designate [my job's server address] as permitted sender) smtp.mail=[some test email]; dkim=neutral (bad format) firstname.lastname@example.org; dmarc=fail (p=NONE dis=NONE) header.from=gmail.com
Is it possible to stop Gmail adding 'Spam::' to subjects in these circumstances?