IP pool unblocking or reassignment for tenant

Question

Purchased a Microsoft 365 (Professional email with 50GB of email storage) though a GoDaddy Reseller web hosting.

Before purchasing, the domain was recently transferred from one GoDaddy Reseller Account to another GoDaddy Reseller Account. Note: the 2 accounts are under the same GoDaddy Reseller company. In short, it is just an "account change" or change in Customer #.

When I checked the DNS entry for the Tenant ID, I can see it has already changed.

The old Tenant ID is: TXT @ NETORGFT12345678.onmicrosoft.com (example only)

New Tenant ID: TXT @ NETORGFT88888888.onmicrosoft.com (example only)

For the sake of discussion, let's call the Microsoft email account as "******@companydomain.com".

When sending emails via Outlook web interface, the recipients receive the email. Responses are also being received back without any issues.

Now, I used the Microsoft 365 email (@companydomain.com) as an email for WP Mail SMTP, which is a plugin for WordPress. This plugin ensures deliverability of emails, specifically, notification emails from online web forms. Example, when somebody fills up a contact form online, those captured data will be sent to the website owner's email as 'Leads". The email that sends this is the Microsoft Office 365 account (@companydomain.com), configured in WP Mail SMTP plugin.

Assuming the website owner's email is ******@gmail.com (the recipient), nothing arrives to this gmail account. However, when testing the WP Mail SMTP plugin, it shows "success". Looking in the inbox of ******@companydomain.com, the captured data / lead info is there. Then after around 2 minutes, there is another email in the inbox that says:

"Delivery has failed to these recipients or groups:

@gmail.com (@gmail.com)

Your message wasn't delivered because the recipient's email provider rejected it.

Diagnostic information for administrators:

Generating server: SJ0PR05MB10049.namprd05.prod.outlook.com

******@gmail.com Remote server returned '550 5.7.708 Service unavailable. Access denied, traffic not accepted from this IP. For more information please go to http://go.microsoft.com/fwlink/?LinkId=526653 AS(7910)'

Original message headers:

Received: from BYAPR05MB6037.namprd05.prod.outlook.com (2603:10b6:a03:d9::18)
 by SJ0PR05MB10049.namprd05.prod.outlook.com (2603:10b6:a03:4ec::14) with
 Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9203.12; Mon, 13 Oct
 2025 11:26:38 +0000
Received: from BYAPR05MB6037.namprd05.prod.outlook.com
 ([fe80::1a7e:668c:8807:fbb8]) by BYAPR05MB6037.namprd05.prod.outlook.com
 ([fe80::1a7e:668c:8807:fbb8%3]) with mapi id 15.20.9203.009; Mon, 13 Oct 2025
 11:26:38 +0000
From: Company Name  <******@companydomain.com> 
To: "******@gmail.com" <******@gmail.com>
Subject: New message from Company's Online Contact Form

Again, it is important to note that using ******@companydomain.com via Outlook web interface, any recipient can receive the email and their responses are also being received back without any issues.

The Microsoft 365 email: ******@companydomain.com only encounters errors if it used as the email account for the WP Mail SMTP WordPress plugin.

Based on the error message, what could be the problem?

I suspect the new tenant ID belongs to an IP pool that is blocked within the Microsoft network. I am thinking this IP was assigned by GoDaddy since it was purchased via a GoDaddy Reseller.

I have setup the SPF, DMARC and DKIM records and verified all is good.

One thing I noticed is that the actual email notification is being received in ******@companydomain.com, then after around 2 minutes, another message arrives that contains the error message (just like the one I posted above). This means, the WordPress setup is passing the online web form captures properly, but the actual email does not get sent out to the intended recipient. It just stays in the Microsoft network.

I have Googled LinkId=526653 AS(7910) error, and it says:

This is a Microsoft bounce error message, 550 5.7.708 Service unavailable. Access denied, traffic not accepted from this IP... which indicates that the email was rejected because the sending IP address has a low reputation. This typically occurs with new Microsoft 365 accounts or when using a third-party service that sends mail from a shared, low-reputation IP address. 

My concern now is, how do I change my Tenant's IP outbound IP pool to a "clean" one, or should I call it, "request a reputation reset" or "IP reassignment"?

Thank you very much to those who will answer.

Answer 1

Hi NWLSS, Thanks for posting to Microsoft community, yes, you're right to suspect the issue is with the IP reputation of your Microsoft 365 tenant, especially since it was provisioned via a GoDaddy reseller.

The 550 5.7.708 Access denied, traffic not accepted from this IP, this means Microsoft is rejecting emails from your tenant due to a low-reputation IP, common with new tenants or recently migrated accounts, Shared IP pools used by resellers and Trial accounts, your DNS records (SPF, DKIM, DMARC) are fine this issue is separate.

To fix this, Contact Microsoft Support then request an IP exception for your tenant simply, go to Microsoft 365 Admin Center then Create a support ticket like Error 5.7.708 – new tenant via GoDaddy reseller, request IP exception then

Also, Use the Office 365 Delist Portal, you’ll need the sending IP used by WP Mail SMTP (check headers/logs). Here’s the link: https://sender.office.com

Also, Contact GoDaddy then ask if they can reassign your tenant to a clean IP pool and escalate the issue to Microsoft here’s the link: https://www.godaddy.com/help/contact-us

For Emails work via Outlook Web but fail via WP Mail SMTP likely due to different sending paths (SMTP relay or Graph API), which may use the blocked IP.

I hope this helps you out, let me know how it goes.

Chard