Tsohost Help Centre

Affected Services

Some emails to Hotmail.com or Outlook.com returned (all services)

Resolved Nov 2nd, 16:09 - Mar 13th, 14:27 GMT


Completeabout 1 year ago

We are no longer receiving mass bounces from Microsoft, and are satisfied this issue is resolved.

Updateabout 1 year ago

Some legitimate emails are still being blocked by Microsoft. Click the title for more info.

Updateabout 1 year ago

Dear Customers,

In the past month, Microsoft have changed their spam filtering and made it extremely aggressive and this has led to some legitimate customer emails being blocked with a message like:

550 5.7.1 Unfortunately, messages from [] weren't sent

This is caused by "bad neighbour effect" - another customer who happens (by chance) to be on the same IP address as you has sent messages which Microsoft deem to be spam. We have thousands of IP addresses in use but the nature of shared hosting is that more than one customer will share a particular IP.

We do our utmost to stop customers abusing our service, whilst still allowing (limited) mass mailing for newsletters, website generated mail, etc. However sometimes a spam message might be allowed through and, if the IP address sends a relatively low volume of mail, this might be enough for other customers to be blocked.

When this happens we will act swiftly to suspend the spammer and to either change the IP or appeal the block with Microsoft depending on the severity of the block.

We understand how important mail delivery is to all customers. We get better every day at preventing outbound spam and the number of IPs getting blocked has reduced massively. However, if you are affected by such an issue, please don't hesitate to get in touch by live chat, phone or support ticket.

This is affecting a lot of service providers and we are working with them and with Microsoft to understand how we can work better together to protect our mutual customers.

Thank you for your patience and understanding.

Kind Regards,

Adam Smith
Brand Director