MessageLabs sending bounce backs

[Nate Long]

I am an MSP for a client that is having issues sending emails to any Yahoo or AOL account. Each email sent is immediately bounced back with the error: 550 5.0.350 Remote server returned an error -> 553 you are trying to use me [server-30.tower-248.messagelab;s.com] as a relay, but I have not been configured to;let you [104.47.66.43, mail-mw2nam12lp2043.outbound.prot;ection.outlook.com] do this. Please visit;www.symanteccloud.com/troubleshooting for more details;about this error message and instructions to resolve;this issue. (#5.7.1)

I have gone through MXToolbox.com, DNSStuff.com, SymantecCloud.com, and any other site I can find related to Yahoo/AOL/MessageLabs/Symantec to confirm there are no blacklists or bad reputation found for my client or the IP address reported by Office365.

I have submitted a support request with Yahoo but they are not answering. AOL support is the same as Yahoo.

I need someone with Symantec/MessageLabs to review their filter/config to see why this is happening.

[Nate Long]

I am still having issues with this and no one is responding to any of the support tickets.

[Martin Line]

A few things spring to mind, but as you haven't mentioned the customer I can't check anything myself;

1. Does the customer configured their outbound IP routes in ClientNet? (Email Services > Outbound Routes menu, Sending Server IP Addresses section)
2. Is the domain of the sending email address for those emails listed on the Domains page, either in 'My Domains' or 'Third Party Domains'? (Email Services > Domains)
3. Have you tried the Email Delivery Troubleshooting Tool? (Tools menu)

[Nate Long]

The client does not use any Symantec/MessageLabs/Security.cloud products.

They are sending to Yahoo and AOL through Office365 hosted exchange.

They have a second domain hosted through the same tenant with Office365 and it is able to send to Yahoo and AOL without issues.

 

 

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[Nate Long]

Any other suggestions? Still having the issue.