If your VPS is sending out spam or attempting to harvest email addresses then you can expect your IP address to be blacklisted, but every now and then Microsoft seems to be overly aggressive in adding individual IP's or even complete network ranges to their blacklist for reasons we don't understand. Please note that Tilaa is not the only hosting provider affected by this aggressive policy.
If you are added to their blacklist you should get an email delivery issue notification from your mailserver stating something along the lines of:
550 SC-001 (BAY004-MC4F9) Unfortunately, messages from x.x.x.x weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.
If you find that you experience email delivery issues to Hotmail or Live.com email addresses please first verify your VPS has not actually been sending out spam. When we receive spam or abuse reports we will always notify you directly. You should also check your system logfiles to ensure no actual spam has been sent out (i.e. by compromised websites or accounts) and your own emails are not considered spammy.
Next, verify that your domain set up is correct. For email delivery to Hotmail/Live.com and others it's important to set up a DMARC policy, enable DKIM to sign outgoing emails and set up SPF to specify which hosts can send email on your domain's behalf. Finally make sure the forward (A) and reverse (PTR) DNS hostname of your mail-server are set and match up.
We recommend you double-check your domain settings and possible listing on other blacklists using these tools:
If you're confident no abuse has been coming from your VPS and your domain has been properly set up we recommend you to submit a delisting request at:
If you get notified your IP is "eligible for mitigation" your IP address should be able to deliver email to Hotmail/Live.com without further issues. In most cases the issues are resolved within 24 hours.
Update: This problem seems to have gotten worse in recent months. If anyone at Microsoft is reading this we'd love to get in touch with the Hotmail engineering team to figure out what's going on.