Microsoft rejecting email from disroot

Microsoft’s live.com is rejecting emails this morning, generating the same error as noted previously in this problem.

host live-com.olc.protection.outlook.com[104.47.58.161]
    said: 550 5.7.1 Unfortunately, messages from [178.21.23.139] werent sent.
    Please contact your Internet service provider since part of their network
    is on our block list (S3140). You can also refer your provider to
    http://mail.live.com/mail/troubleshooting.aspx#errors.
    [BN8NAM11FT027.eop-nam11.prod.protection.outlook.com] (in reply to MAIL
    FROM command)

There’s nothing obvious listed against disroot.org on mxtoolbox.com. I don’t know what else to do except report it here.

Thanks.

We have been trying to get any response from microsoft and this is what we got:

Hello,

As previously stated, your IP (178.21.23.139) do not qualify for mitigation at this time. I do apologize, but I am unable to provide any details about this situation since we do not have the liberty to discuss the nature of the block.

At this point, I would suggest that you review and comply with Outlook.com’s technical standards. This information can be found at https://postmaster.live.com/pm/postmaster.aspx.

We regret that we are unable to provide any additional information or assistance at this time.

Best regards,

Outlook.com Deliverability Support

So basically “We blocked you, won’t tell you why. Have a good day”