How to configure a mailing list to never hold anything for moderator approval and avoid these messages?
PLESK_INFO: Your mail to ‘list_name’ with the subject
Is being held until the list moderator can review it for approval.
The reason it is being held:
Post by non-member to a members-only list
Go to Domains > example.com > Email Addresses > Mailing Lists tab and click Manage the list next to the address in question.
Go to Action to take for postings from non-members for which no explicit action is defined and select Accept to let non-member postings to get through.
Click Submit Your Changes.