why when i send emails do i get message 4.7.1 grey listed for 900 seconds
Hi Ian,
Graylisting is an antispam method used by mail servers, it seems the recipients’ server is rejecting your message. Unfortunately, there usually isn’t much you can do to change this behavior from your side.
https://answers.microsoft.com/en-us/msoffice/forum/all/how-to-prevent-greylisting/c0999c64-8c39-460d-9433-77f2c5a29894
https://forum.iredmail.org/topic8129-iredmail-support-smtp-auth-471-recipient-address-rejected-greylisting.html
http://www.softwareprojects.com/resources/traffic-attract-customers/t-greylisting-yet-another-reason-why-emails-to-your-1210.html
https://www.pcreview.co.uk/threads/how-do-i-prevent-451-4-7-1-greylisting-in-action.3118030/