Resolved -
No further deliverability issues have been observed. The incident is resolved.
Nov 20, 14:15 CET
Update -
We are seeing significant improvements in mail deliverability to Yahoo. We are still monitoring the situation.
Nov 19, 10:31 CET
Update -
We are still seeing Yahoo throttling mails sent through our platform. In order to work around this we will be adding additional IP-addresses to sent these e-mails.
Yahoo remains very restricted however, and a definitive solution will require their cooperation.
Nov 18, 17:23 CET
Monitoring -
Since 13:10 we no longer see mail deliverability issues for mails sent to Microsoft.
Mails sent to Yahoo remain throttled. We are still waiting for their response in order to fully resolve the issue.
Nov 17, 17:32 CET
Identified -
We have determined that the issue was caused by spambots abusing a large amount of unprotected webforms of our clients. We have contacted these clients and asked them to resolve the problem on their websites.
We have also contacted Microsoft and Yahoo to delist our IP-addresses from their blacklists. Microsoft has confirmed they will delist our IP-adresses within 24-48 hours. We are still waiting for a response from Yahoo.
Nov 17, 13:09 CET
Investigating -
We are experiencing reduced deliverability for outgoing e-mails sent through our our mail-filter to specific providers such as Microsoft (@outlook,@live,@hotmail,@office365) and Yahoo (@yahoo) due to a blacklisting. We are investigating the cause and taking actions to resolve this issue.
Nov 17, 11:27 CET