the recipient's mailbox is full and can't accept messages now. Please try resending your message later, or contact the recipient directly.

Question

Hello,

I have unusual issue with office 365. We have some mail groups with plenty recipients in each group. Today we receive error alert - The recipient's mailbox is full and can't accept messages now. Please try resending your message later, or contact the recipient directly". But the group don't use physical storage. Each account use it's own mailbox. I can't understand why this message appeared. Do you have any ideas?

Answer 1

Hi @Georgiev Ventsislav,

Even though each group member has their own mailbox, they all use a shared mailbox as well to receive and manage messages sent to the group. This shared mailbox has a default storage quota of 50GB, and if that limit is exceeded, messages sent to the group will bounce back with the error message you encountered.

To fix this problem, you will need to free up some space in the Microsoft 365 group mailbox by either deleting old or unnecessary emails, or archiving them to another location. You can also implement best practices in managing the Microsoft 365 group mailbox size to avoid it reaching its quota limit in the future.

You can monitor the group mailbox using the PowerShell commands in this article: Microsoft 365 group mailbox size management.

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