i cant send mails

Question

Hi

I have a huge problem, I can't send emails to certain companies, and they can't send me any either, I always get error 554, what should I do please, does anyone know this problem? As already mentioned, I can't send to certain companies, but to others, it can be ahead?

Message Hops
FROM	TO	WITH	RELAY TIME
AM7PR01MB6801.eurprd01.prod.exchangelabs.com	AM7PR01MB6801.eurprd01.prod.exchangelabs.com	mapi	1 sec
AM7PR01MB6801.eurprd01.prod.exchangelabs.com	DBAPR01MB7029.eurprd01.prod.exchangelabs.com	Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384)	*

Error:	550 5.0.350 Remote server returned an error -> 554 Your access to this mail system has been rejected due to poor reputation of a domain used in message transfer

Answer 1

Hello Hüseyin BEKTAŞ1, Good day!Thank you for posting to Microsoft Community. We are happy to help you. As per the description you have shared, we understand that you have a concern with can't send emails to certain companies. Typically, you should check your domain setting in your admin center and see if the affected domain status is healthy. if not you should check your DNS records once again.

However, to better understand the issue and provide solution, we need more details from you, please kindly provide us the following information. Thank you.

• Did you recently transfer your domain to another hosting. if yes you should check the configuration of the MX and TXT fields if it is correctly set up.
• Are you using third party to analyze all incoming and outgoing emails, if yes you should create an Anti-spoofing policy to take no action for the sender's IP address on the third party side.
• Based on the error you are getting the issue can be to the recipient's side . Check this link: https://learn.microsoft.com/en-us/exchange/troubleshoot/email-delivery/ndr/fix-error-code-550-5-0-350-in-exchange-online.
• please can you enable your DKM if it is possible and make a test on the system to make sure of the domain healthy? it can be that the recipient side he may have setting policy for external domain.
• Please to analyze the mailflow do the extended message trace and share the csv file with us. it will helps to find the real cause. Reference: Message trace in the modern EAC in Exchange Online | Microsoft Learn. you need to be admin. Note: Due to some data security, if it is convenient, you may also share above requested information in private message. 

Below are the steps to open private message: 

- To View private messages option > click on Profile Picture at top of the right side > Select My Profile option
- [![](https://learn-attachment.microsoft.com/api/attachments/ad49966c-b4ce-443e-b54b-6ceb557c6bf9?platform=QnA

Answer 2

I also thought that it could possibly be due to the ip address, but even if I send mails directly via office.com, the same thing happens, it is more due to the domain as it seems. How can I solve this problem?

Answer 3

Are you using 3rd party email service and sending email from new IP addresses?

If so, IP addresses not previously used to send email typically don't have any reputation built up in MS systems. As a result, emails from new IPs are more likely to experience delivery issues. Once the IP has built a reputation for not sending spam, EOP typically allows for a better email delivery experience.