TO whom it may concern Good day Now we're facing a liit bit serious problem. We're a Germany company's subsdiary company. and recently they said many mails we sent to them were in Spam or MIA(we communicated for more than 8years) now our mail account in their spam? And not only our Headquarter but also some our clients. They can't receive mails,too. Also some info: we are using a public net IP shared with thousands of people. we don't have a exclusive static public net IP. And out Ip address is 47.xxx.xx.xxx until last week. This IP is in Spamhaus's PBL(maybe that's the reason). But this week our IP address is 58.xxx.xxx.xxx(Dynamic Ip address) and it's very clear from each anti-spam organization. Just for me, all of sudden I can chat through e-mail with our headquater. So I'm thinking maybe Changed IP is the reason? But People from headquater tell me that my colleague's mail still in their Spam. Yeah they can receive them but cost extra energy to move them out. Please help me to solve this tricky problem. Best regards Mike Liu

Hi @Mike Liu Welcome to Microsoft Q&A！ Actually the "Outlook Management" tag is for general questions about the Outlook desktop client. So, before we go on, could you clarify which email system you and your headquarter are using so that I can see if a more appropriate tag can be added under the thread? Is it Exchange on-premises or Exchange Online? We're a Germany company's subsdiary company. and recently they said many mails we sent to them were in Spam or MIA(we communicated for more than 8years) now our mail account in their spam? And not only our Headquarter but also some our clients. They can't receive mails,too. Mails might be sent to spam for various reasons, so it might be hard to determine the root cause in a timely manner. For other clients who cannot receive your mails, do you mean the mails are also sent to the Junk Email folder? Did senders in your organization get any non-deliverable bounce back messages? Moreover, if possible, you can work with one of the receivers' side to see if you are able to get a sample of the message header of one problematic mail. Then you can read it using Message Header Analyzer and check the Authentication-results header to see if any clues can be found. Somes times mails could be sent to spam due to the SPF or DKIM failure. One more link below for reference: <a href="https://superuser.com/questions/1236471/is-our-dynamic-ip-causing-our-mail-to-go-into-spam-despite-clean-mailserver#:%7E:text=I%20mark%20this%20as%20correct%20answer%20regarding%20my%20question%2C%20as%20point%20Nr%201%20is%20correct.%20The%20spam%20issue%20was%20effectively%20NOT%20related%20to%20the%20IP%20address%2C%20but%20to%20the%20fact%20that%20the%20ISP%20sent%20the%20emails%20through%20a%20domain%20different%20from%20the%20address%20in%20the%20FROM%20field%2C%20without%20providing%20any%20DKIM." rel="ugc nofollow">is our dynamic IP causing our mail to go into spam, despite clean mailserver? (Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.) If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Suddenly Our mails were blocked by other mail server(include some old friend server)

Accepted answer

Yuki Sun-MSFT 41,201 Reputation points Microsoft Vendor

2023-07-11T06:18:15.5066667+00:00

Hi @Mike Liu

Welcome to Microsoft Q&A！

Actually the "Outlook Management" tag is for general questions about the Outlook desktop client. So, before we go on, could you clarify which email system you and your headquarter are using so that I can see if a more appropriate tag can be added under the thread? Is it Exchange on-premises or Exchange Online?

We're a Germany company's subsdiary company. and recently they said many mails we sent to them were in Spam or MIA(we communicated for more than 8years) now our mail account in their spam? And not only our Headquarter but also some our clients. They can't receive mails,too.

Mails might be sent to spam for various reasons, so it might be hard to determine the root cause in a timely manner.
For other clients who cannot receive your mails, do you mean the mails are also sent to the Junk Email folder?
Did senders in your organization get any non-deliverable bounce back messages?

Moreover, if possible, you can work with one of the receivers' side to see if you are able to get a sample of the message header of one problematic mail. Then you can read it using Message Header Analyzer and check the Authentication-results header to see if any clues can be found. Somes times mails could be sent to spam due to the SPF or DKIM failure. One more link below for reference:
is our dynamic IP causing our mail to go into spam, despite clean mailserver?
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.
Please sign in to rate this answer.
Mike Liu 20 Reputation points

2023-07-11T07:14:33.83+00:00

Dear Yuki Sun

Thanks for your quick response.

haha,it's the first time I come and I found out that Tagging is not easy..you can't choose them,you just type them..but I know little about these tags.

we're using office 365(International and businness ver,outlook.office365.com),our headquater maybe is https://prod.outlook.com/ this ver.. And we're using exchange online.

For our headquater,our mails were in Junk folder. For some clients,mails just MIA.

And none of us received bounce back e-mail.

Also,it's a little bit hard to let a oversea receiver gives us the message header.

Can I just let my colleague(next to me) send me a mail and then annalyze?

I'm kind sure that we didin't open SMTP authen and DKIM. Is this a problem?

An dynamic IP plus Non-open authen. Maybe it's a liitle bit unsafe.

But I checked our IP address,we're not on any anti-spam organization's white list like Sapmahus.

So this a little bit confuses me.

Thanks

Mike Liu 20 Reputation points

2023-07-11T07:19:40.46+00:00

Here's a message header my colleague sent to me..may it can tell sth.

Received: from SEYPR06MB5766.apcprd06.prod.outlook.com (2603:1096:101:b9::13) by KL1PR0601MB4243.apcprd06.prod.outlook.com with HTTPS; Mon, 10 Jul 2023 10:35:39 +0000 Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=xxx.xxx; Received: from KL1PR06MB6757.apcprd06.prod.outlook.com (2603:1096:820:102::9) by SEYPR06MB5766.apcprd06.prod.outlook.com (2603:1096:101:b9::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6565.30; Mon, 10 Jul 2023 10:35:34 +0000 Received: from KL1PR06MB6757.apcprd06.prod.outlook.com ([fe80::491c:18e5:8264:55bb]) by KL1PR06MB6757.apcprd06.prod.outlook.com ([fe80::491c:18e5:8264:55bb%5]) with mapi id 15.20.6565.028; Mon, 10 Jul 2023 10:35:34 +0000 Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: binary From: xxx<xxx@xxx.xx> To: xxx<xxx@xxx.xx> CC: xxx<xxx@xxx.xx> Subject: =?gb2312?B?16q3ojogNy8xMbeiu/UgIE1GS1NPMjMwNTE2ODYgILyxo6E=?= Thread-Topic: =?gb2312?B?Ny8xMbeiu/UgIE1GS1NPMjMwNTE2ODYgILyxo6E=?= Thread-Index: AdmzGRJ7tFbh/gm+QgmqBMDHxid/swAAMugg Importance: high X-Priority: 1 Date: Mon, 10 Jul 2023 10:35:34 +0000 Message-ID: <KL1PR06MB6757ED766710FF677AEA13D58C30A@KL1PR06MB6757.apcprd06.prod.outlook.com> References: <KL1PR06MB67570A9273EE2C666E72BC038C30A@KL1PR06MB6757.apcprd06.prod.outlook.com> In-Reply-To: <KL1PR06MB67570A9273EE2C666E72BC038C30A@KL1PR06MB6757.apcprd06.prod.outlook.com> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: yes X-MS-Exchange-Organization-SCL: 1 X-MS-TNEF-Correlator: <KL1PR06MB6757ED766710FF677AEA13D58C30A@KL1PR06MB6757.apcprd06.prod.outlook.com> MIME-Version: 1.0 X-MS-Exchange-Organization-MessageDirectionality: Originating X-MS-Exchange-Organization-AuthSource: KL1PR06MB6757.apcprd06.prod.outlook.com X-MS-Exchange-Organization-AuthAs: Internal X-MS-Exchange-Organization-AuthMechanism: 04 X-MS-Exchange-Organization-Network-Message-Id: 613ecdb4-d448-490b-ccb9-08db813164bc X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: KL1PR06MB6757:EE_|SEYPR06MB5766:EE_|KL1PR0601MB4243:EE_ Return-Path: xxx<xxx@xxx.xx> X-MS-Exchange-Organization-ExpirationStartTime: 10 Jul 2023 10:35:35.1404 (UTC) X-MS-Exchange-Organization-ExpirationStartTimeReason: OriginalSubmit X-MS-Exchange-Organization-ExpirationInterval: 1:00:00:00.0000000 X-MS-Exchange-Organization-ExpirationIntervalReason: OriginalSubmit X-MS-Office365-Filtering-Correlation-Id: 613ecdb4-d448-490b-ccb9-08db813164bc X-Microsoft-Antispam: BCL:0; X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:zh-cn;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:KL1PR06MB6757.apcprd06.prod.outlook.com;PTR:;CAT:NONE;SFS:;DIR:INT; X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jul 2023 10:35:34.5924 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 514683d2-ded3-41bb-b4dd-666739417aae X-MS-Exchange-CrossTenant-AuthSource: KL1PR06MB6757.apcprd06.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-Network-Message-Id: 613ecdb4-d448-490b-ccb9-08db813164bc X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: NoxFuRUqpYDlDiHHurW/Obr5fLF8GP3BQ55dO1tEc/QXgqAckrmlUMjWHvoB6bWpLJlct/h9XOPYkrRg+UpT2kTqZYOHy8kIXdZ+SBbDJCk= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SEYPR06MB5766 X-MS-Exchange-Transport-EndToEndLatency: 00:00:05.1691348 X-MS-Exchange-Processed-By-BccFoldering: 15.20.6565.027 X-Microsoft-Antispam-Mailbox-Delivery: ucf:1;jmr:0;auth:0;dest:C;OFR:CustomRules;ENG:(910001)(944506478)(944626604)(920097)(425001)(930097); X-Microsoft-Antispam-Message-Info: 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

Yuki Sun-MSFT 41,201 Reputation points Microsoft Vendor

2023-07-11T09:10:50.27+00:00

Hi @Mike Liu,

we're using office 365(International and businness ver,outlook.office365.com),our headquater maybe is https://prod.outlook.com/ this ver.. And we're using exchange online.

Appreciate the clarification and I've added the tag "Exchange Online Management" which can better reflect your situation.

As for the message header, seems like youBy the way, considering that it's a public community, I've removed the email addresses and domain name in the message header you shared. It's suggested to remove all these data in your future posts as well for privacy concern. Thanks!

Mike Liu 20 Reputation points

2023-07-13T01:20:20.5966667+00:00

Dear @Yuki Sun-MSFT

thanks for your kind action to protect my privacy.

Also,is there any further information for this case？

And I'd like to ask,if we want to add DKIM,it said we need to add CNAME to DNS,which DNS?

We have a local dns we deployed ourselves it's for our local domian..

But I guess we're using an online mail,so maybe we need to add CNAME to our net DNS ,right?

If so,maybe we need to contact our ISP beacuse we don't have a exclusive DNS for internet connection.

Best regards

Yuki Sun-MSFT 41,201 Reputation points Microsoft Vendor

2023-07-13T08:09:48.8766667+00:00

Hi @Mike Liu,

Yes, you'll need to contact your ISP if you want to set up the DKIM.

Moreover, for your current situation, you can consider reaching out to the impacted receivers' side to see if they can add your domain to their allow list or using some other methods as mentioned in the link below to prevent mails sent from your organization going to spam:
https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/create-safe-sender-lists-in-office-365?view=o365-worldwide

Mike Liu 20 Reputation points

2023-07-14T07:34:25.5733333+00:00

Dear @Yuki Sun-MSFT

thanks for your help. I will try to use method you say.

Best regards
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