Microsoft Warns Of Gmail Spam Error

John Lister's picture

Microsoft has warned Gmail is blocking messages from some Outlook users. It’s shared a workaround for the problem, caused by an overactive spam filter.

The problem appears to be affecting users who have an Outlook email address that ends with a specific country domain rather than “.com”. When they send a message to a Gmail account, it’s undelivered. Instead, the sender gets an automated response reading: Remote server returned message detected as spam -> 550 5.7.1 [[ IPAddress]] Gmail has detected that this message;is likely suspicious due to the very low reputation of the sending;domain. To best protect our users from spam, the message has been;blocked. For more information, go to Why has Gmail blocked my messages?
Google has yet to comment specifically on the issue. It has a general support article that says in cases like this, only a “subset” of messages are being blocked.

Spam Filter Overactive

Such blocking goes a step beyond the usual Gmail setup of putting suspicious messages in a dedicated spam folder where users can manually review messages and retrieve any that were mislabelled. Instead the message is completely blocked and the intended recipient will have no idea it was not sent.

It’s possible the problem is linked to a tougher Google spam policy that took effect this month. It’s now blocking messages completely from “bulk senders” who don’t follow guidelines on authenticating their messages. (Source:

If that is the case, something has certainly gone wrong as Google shouldn’t be treating all messages from an Outlook country domain as being from the same sender.

Alias Address Workaround

Microsoft says it is trying to address the issue from its end. In the meantime it says users who need to message a Gmail recipient should use Outlook’s “Add an alias” feature and create an extra address ending in

By setting up an alias rather than a new account, users can send and receive messages from both addresses on the same account. (Source:

What’s Your Opinion?

Have you come across this problem? Do you often get messages returned as suspected spam? Are spam filters too strict or not effective enough?

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