STILL CANNOT send or reply to e-mails for @domain.net addresses-WHY?

Question

STILL CANNOT send or reply to e-mails for @domain.net addresses-WHY?

Ron 0

starting yesterday cannot send t or answer emails to domain.net. never happened before and has never been a problem. What can be done to fix problem?

Ron 0 Reputation points

2025-11-06T21:11:40.71+00:00

it's happening in Outlook. Problem sending to comcast.net. Don't understand what you mean by removing and re-adding the account> My outlook account?

5 answers

Your answer

Ron 0 Reputation points

2025-11-06T21:11:40.71+00:00

it's happening in Outlook. Problem sending to comcast.net. Don't understand what you mean by removing and re-adding the account> My outlook account?

Answer 1

Ron 0

Annual personal I think.

Vergil-V 12,975 Reputation points Microsoft External Staff Moderator

2025-11-17T14:51:47.5966667+00:00

Hi @Ron
For specialized support regarding mail routing in your Microsoft 365 Personal subscription, I recommend reaching out to the Microsoft Support Team by following these steps:

Step 1: Sign in to Contact - Microsoft Support

Step 2: Enter “There’s a problem with the recipient’s mailbox” and select Get help

Step 3: Choose Contact Support

Step 4: Select Product and Services, then choose the appropriate Category as shown in the example image

Step 5: Select the available support option

Additionally, you may also contact Comcast support to investigate the issue on their side.

In the meantime, I would appreciate it if you could respond to the questions in my previous message.
Thank you for your cooperation.

Answer 2

Ron 0

don't have an IT person. I signed into Microsoft 265 and sent from that sign in to a comcast email address and still didn't go through

Here is message I received:

Delivery has failed to these recipients or groups:

[St. [Moderator note: personal info removed] and St. [Moderator note: personal info removed] There's a problem with the recipient's mailbox. Please try resending the message. If the problem continues, please contact your email admin.

The following organization rejected your message: <Removed PII>.sys.comcast.net.

Vergil-V 12,975 Reputation points Microsoft External Staff Moderator

2025-11-14T14:18:45.7833333+00:00

Please note that our forum is a public platform, and we will modify your response to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data.

Hi @Ron
Thank you for sharing these details.

Since you mentioned that you currently do not have an IT team, could you please confirm your Microsoft 365 subscription type? Does it fall under one of the following categories?

For individuals: Compare Microsoft 365 Plans & Pricing (Formerly Office 365) - Microsoft Store

For businesses: Microsoft 365 Business Plans and Pricing | No Teams

Additionally, to check whether the issue might be on the recipient’s side, please verify the block list and spam filter settings in Comcast, as well as the server configuration on their end.

When you mentioned signing in to Comcast, could you clarify whether you are signing in through Outlook or directly via the Comcast webmail portal?

Also, are you able to send emails from your Comcast account back to your Microsoft account without any issues?

This information will help us understand whether both servers can communicate properly or if Comcast is rejecting messages from your Microsoft account.

Since Comcast is outside the Microsoft ecosystem, our resources for troubleshooting their settings are limited. However, your input will help us refine our support and guide you more effectively.

Answer 3

Ron 0

I'm using Outlook on my laptop and do have a subscription to Microsoft 365. Also have same problem with gmail but the Comcast problem is only about a week or so.

Vergil-V 12,975 Reputation points Microsoft External Staff Moderator

2025-11-10T06:40:46.0466667+00:00

Hi @Ron
Thank you for sharing this information

Could you please confirm that the Microsoft account with the Microsoft 365 subscription you mentioned is unable to send emails to the affected third-party mailbox?

If that’s correct, could you also confirm whether the issue occurs in Outlook on the web? This will help us determine whether the problem is isolated to the Outlook desktop app or if it also affects the server side

Additionally, you might want to ask your IT team to run a message trace to identify the mail route, which could help pinpoint the issue. It would also be helpful for them to check any transport rules that might be impacting mail flow.

Furthermore, could you clarify which Outlook interface is currently experiencing the issue:

+Classic Outlook +New Outlook

Understanding these details will allow me to refine my support and provide more accurate guidance. I look forward to your update.
Vergil-V 12,975 Reputation points Microsoft External Staff Moderator

2025-11-11T14:34:45.1366667+00:00

Hi @Ron

I wanted to follow up and see if you've had any progress since our last exchange. If you've have updates, please feel free to share them here.

I'm still available to assist and troubleshoot alongside you, and I appreciate your continued engagement in this matter.

Looking forward to hearing from you.
Vergil-V 12,975 Reputation points Microsoft External Staff Moderator

2025-11-13T15:18:28.42+00:00

Hi @Ron

I just wanted to kindly follow up to see if you’ve had a chance to review my previous response.
I would greatly appreciate any updates you may be able to provide, particularly regarding the usefulness of the information we shared. Your feedback is essential to our ongoing efforts to enhance the quality of our support.

Thanks again for your time, and we look forward to hearing from you

Answer 4

Ron 0

it's happening in Outlook. Problem sending to domain.net. Don't understand what you mean by removing and re-adding the account> My outlook account?

Vergil-V 12,975 Reputation points Microsoft External Staff Moderator

2025-11-07T06:48:55.05+00:00
Please note that our forum is a public platform, and we will modify your question to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data.
Hi @Ron
Yes, when I mentioned removing and re-adding the account, I was referring to your Outlook account.
Could you please confirm a few details for me?

When you say Outlook, are you using Outlook on the web, the desktop app (Classic or New), or the mobile app?

Do you see any Non-Delivery Reports (NDR) or error messages when sending emails to the affected recipient? If so, please share those with me in a private message to protect your privacy.

Does this issue only occur with that specific recipient, or have you noticed it with other third-party mailboxes as well?

Please feel free to reach out if you have any updates or need further assistance. I’m here to help.

Answer 5

Please note that our forum is a public platform, and we will modify your question to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data.
Hi @Ron
Thank you for reaching out to Microsoft Learn Q&A!
I understand how frustrating and inconvenient it can be when you’re unable to send emails. To better understand your situation, could you please clarify the following:

Can your mailbox send emails normally when using webmail?
What type of connection method are you using: POP3, IMAP, or Exchange?
Does the issue occur in Outlook or another email application? If it’s Outlook, is it happening on the desktop app (Classic or New) or the mobile app?

As a quick step, you might try removing and re-adding the account for a simple refresh.

Please know that while our initial response might not resolve the issue right away, your input is incredibly valuable. With a bit more detail, we’ll work together to find the best solution for you.

I look forward to hearing from you soon.

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.

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STILL CANNOT send or reply to e-mails for @domain.net addresses-WHY?

5 answers

Your answer