From Our Email Provider:
On May 6th, 2025 between approximately 6:43pm-12:30am EST an issue occurred resulting in messages for some customers not being sent as expected. The root cause was identified and engineering has since resolved the issue. Email sending returned to its expected state after that time period.
Engineering teams are continuing to monitor email sending and implement further improvements to our systems.
Postmark Support 11:53 EDT - 8 May 2025