We have a client who is using email services with Office 365, when ever the client emails @bigpond.com email addressess a bounce back is received. We have been unable to resolve this with support from Microsoft, any ideas why this would be occuring?
Bounce back is below:
More Info for Email Admins
Status code: 550 5.7.350
When Office 365 tried to send the message to the recipient (outside Office 365), the recipient's email server (or email filtering service) suspected the sender's message is spam.
If the sender can't fix the problem by modifying their message, contact the recipient's email admin and ask them to add your domain name, or the sender's email address, to their list of allowed senders.
Although the sender may be able to alter the message contents to fix this issue, it's likely that only the recipient's email admin can fix this problem. Unfortunately, Office 365 Support is unlikely to be able to help fix these kinds of externally reported errors.
Reported error: 550 5.7.350 Remote server returned message detected as spam -> 550 <******@bigpond.com> recipient rejected. IB603a
DSN generated by: PS1PR0201MB2251.apcprd02.prod.outlook.com
Remote server: extmail.bigpond.com
HOP TIME (UTC) FROM TO WITH RELAY TIME
11:35:36 PM PS1PR0201MB1436.apcprd02.prod.outlook.com PS1PR0201MB1436.apcprd02.prod.outlook.com mapi *
11:35:37 PM PS1PR0201MB1436.apcprd02.prod.outlook.com PS1PR0201MB2251.apcprd02.prod.outlook.com Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) 1 sec
Any assistance would be appreciated.
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My office is using Office365 email hosting with Exchange Online and I've just emailed my personal Bigpond account without any issue.
What is the subject and content of the messages like that are being sent? Is there any chance that they could be suspected of spammy content?
You should also check the domain to make sure it's not on any real-time black lists (https://mxtoolbox.com/blacklists.aspx).
While you're at it, you ask them to BCC you in on one of the problem email sends so you can analyse the message headers. It could be that their SPF record, DKIM or DMARC is causing Bigpond's stupidly sensitive email platform to reject the messages.
I have 2 customer that have experience the same issue, but only on a single Bigpond address. I suspect that Bigpond customer (receiver) had the Telstra Protection subscription.
My first Customer is a business on Office 365, fully setup with SPF and DKIM activated and validated.
The other one is on Hotmail.
Both situation, only 1 of their contact on Bigpond is rejecting their messages, not their other contacts on Bigpond.