Roadrunner Mail servers rejecting office 365 Email.

Is Spectrum aware of this issue? If I sent from my office 365 mail as well as many clients to a residental email getting :


dnvrco-cmimta20 rejected your message to the following email addresses: (
Your message was rejected by the recipient email server. Please check the recipient's email address and try resending your message, or contact the recipient directly. For more tips to help resolve this issue, see DSN code 5.1.0 in Exchange Online - Office 365. If the problem continues, contact your email admin.

dnvrco-cmimta20 gave this error:
<> sender rejected AUP#I-1320



Re: Roadrunner Mail servers rejecting office 365 Email.

I have been dealing with the same problem, except that I use Windows Live. I have called them every day for over a week and each time, they either reconfigure my settings or tell me to use webmail. First I heard "we're working on it." Then I heard "they're not sure that they can fix it." And then I got the old reliable "Just use webmail." Webmail is very basic. Doesn't even allow formatting of text. I can't believe they think this is acceptable service for an internet provider.

Re: Roadrunner Mail servers rejecting office 365 Email.

Multiple users over on the DSL Reports forum are reporting this issue too. Definitely seems to be an issue with servers rejecting emails from Office 365 hosted email accounts. I'll repeat here what I was told by the Spectrum Enterprise support team:

send your delivery failure reports, specifically all message headers and any other relevant information to

I suggest a subject title of "Office 365 Originating Emails undeliverable to"