Forum emails bouncing to new member

[XFdestek]

Just found that a number of forum emails (eg from watched thread notifications) have bounced back from a fairly new member, with their email provider saying they are marked as spam. Not good! Not sure how I can contact them to ask them to mark it as not spam as a DM wlll just lead to another bounced email probably. Any suggestions? Remove the email address from their account and wait for them to log in again maybe?