Missing email on KeyOne

I seem to have an issue receiving an email from a work colleague with an attachment. It goes to my pc fine but not the phone. Yet if I click on the search icon it is there, so it's like I've applied a filter or something unwittingly. Has anyone else had this issue? I am receiving mails with attachments form other people though!

Maybe it's because you don't synchronize all of your mail folders? Take a look and see if your colleague's mail is in another folder (e.q. spam).