OVH IP result blacklisted in some AntiSpam

With Microsoft addresses (hotmail, outlook, live) I get back my mail messages.
Error message reports the IP is blacklisted by some AntiSpam filter.

This is the last one I received:

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: host eur.olc.protection.outlook.com[104.47.14.33]
said: 550 5.7.1 Unfortunately, messages from [51.38.179.249] weren't 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.
[VI1EUR04FT008.eop-eur04.prod.protection.outlook.com]
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It's a big issue for me and my Customers. I need to solve it as soon as possible

Many thanks