I'm working on owa addin with on-send functionality enabled, I got this Load add-ins that are required for your organization when sending a message from shared mailbox account, I disabled and removed the add-in but still got the same thing, any how can I send email from shared mailbox in that case?
it was the on-send functionality that blocks the sending, removing it from the delegated account will make it able to send message, even if the add-in is installed/enabled