Outage in MxToolbox

MailFlow Monitoring Impacted by SpamHaus Blocklisting

Resolved Minor

February 13, 2026 - Started about 18 hours ago - Lasted about 5 hours
Official incident page

Incident Report

We are currently experiencing an issue with our MailFlow Monitoring being impacted by being listed on the SpamHaus blocklist. Our Team is working to have our IPs removed from this list. Due to the nature of our monitoring tools, some of our IP addresses may be listed occasionally on certain RBLs. These listings may cause issues with certain anti-spam appliances/security software and result in a mailflow test message to not be delivered. As we do our best to remove the listings promptly, we recommend you add our IP addresses as a safe/allowed sender to ensure mailflow tests are uninterrupted. 44.194.168.193/32 52.55.244.91/32 18.205.72.90/32 18.209.86.113/32 We apologize for the inconvenience.

Components affected

MxToolbox Mailflow MxToolbox Monitoring

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Latest Updates ( sorted recent to last )

RESOLVED about 13 hours ago - at 02/13/2026 09:36PM

This incident has been resolved.

MONITORING about 16 hours ago - at 02/13/2026 06:38PM

Our IPs for MailFlow have just been removed from the SpamHaus listing...we are continuing to monitor the MailFlow connectivity issue that was being impacted by this listing.

IDENTIFIED about 18 hours ago - at 02/13/2026 04:46PM

We are currently experiencing an issue with our MailFlow Monitoring being impacted by being listed on the SpamHaus blocklist. Our Team is working to have our IPs removed from this list.

Due to the nature of our monitoring tools, some of our IP addresses may be listed occasionally on certain RBLs. These listings may cause issues with certain anti-spam appliances/security software and result in a mailflow test message to not be delivered. As we do our best to remove the listings promptly, we recommend you add our IP addresses as a safe/allowed sender to ensure mailflow tests are uninterrupted.

44.194.168.193/32
52.55.244.91/32
18.205.72.90/32
18.209.86.113/32

We apologize for the inconvenience.

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