One of the email addresses on our account has started getting the following bounceback message to all emails sent out and we don't know why.
"Your message couldn't be delivered because you weren't recognized as a valid sender. The most common reason for this is that your email address is suspected of sending spam and it's no longer allowed to send email. Contact your email admin for assistance."
We haven't changed any settings, we are sending to people we are regularly in contact with, and are not having a problem sending from another email address on the account. Would appreciate any info on this.