I'm using CF 7 for two years now, so far no problems. But since two weeks my clients with hotmailaccounts are not receiving the autoresponse mails anymore. Other accounts, like Gmail etc still receive the e-mails.
My hosting provider discovered the following error:
"550 5.7.0 (BAY0-MC4-F44) Message could not be delivered. Please ensure the message is RFC 5322 compliant."
What can I do to solve this issue?
Anyone with the same problem?
Thanks for the help!