We are actively mitigating this issue. You might see deferrals in your webhooks or UI instead of delayed processing. Please note emails are still being retried.

This is caused by an increase in volume due to the ongoing incident with Spamhaus listing, which is being resolved and the delisting is being propagated.

This issue does not impact Microsoft 365 (Outlook 365) addresses nor other providers.

Broadcast is also not affected by the issue.

Our sincere apologies for the inconvenience.