We've received reports of mail delivery being refused from applications like TRAQ and mailing lists to kgh.kari.net, providencecare.ca and krcc.on.ca email addreses, which use mail.queensu.ca to deliver mail. Delivery reports forwarded to ITS indicate these domains are using the services of Proofpoint.com which has marked one of our IPs with a poor reputation and blacklisted it.

A check of other notable mail-related blacklists indicate no other sites are blacklisting any of our mail gateways, and we've submitted a request with Proofpoint to delist us from their blacklist. Unfortunately, it is beyond our control whether they do so or for knowing the timeline when/if it may happen. Although KGH, Providence Care and KRCC have been identified as using Proofpoint.com's service, they are not necessarily the only domains affected, as any user's of Proofpoint will result in the same delivery refusal messages.

For some cases, such as with mailing lists, sending the blocked messages directly to affected recipients may be a temporary workaround until Proofpoint removes the block. Alternatively, users with an @queensu.ca email address can use it instead as delivery for @queensu.ca addresses continues as normal. (If users want to forward their @queensu.ca email to their KGH, ProvidenceCare and/or KRCC mailbox, the IT Support Centre can assist with setting up your mailbox to keep a copy of messages being forwarded to external destinations and ensure no mail is lost should events like these occur in the future.)