After updating passwords, I can no longer send eMails via Outlook

I have the same problem for the same time frame

I have the same issue!

This is my 3rd day with the following issue.   I have called & chatted with Xfinity technicians 3 times and they were clueless.  Each one wasted over an hour of my time reading the same script with no resolution.  While chatting with 1 technician yesterday, I was transferred to 2 other technicians.  Each one started over with the same script until I finally said enough is enough and quit the chat.  The very first technician that I spoke to on Sunday, said it was Microsoft's issue. I called Microsoft but was not able to speak to a human.  I have posted on multiple boards with no resolution.

On 12/17/23, I logged into xfinity.com and was asked to update my password.  I have 4 eMail accounts across 2 different desktops for different family members.  I changed the password on two of my accounts.  I then went into Outlook on my desktop and updated the password for those 2 accounts.  Right after doing that, I was no longer able to send eMails via Outlook.  I was able to receive eMails..  This happened on all 4 accounts at the same time even though I only changed password on 2 of them.  I then logged back into Xfinity.com and was able to both send and receive emails.  It only stopped working on Outlook.

I then tried my iPhone and iPad and received the same error message.

Here are the error messages that I received when trying to send an eMail.

Sending reported error (0x800CCC67).  ESMTP server temporarily not available, please contact support.

I have tried everything that I could find info on. I turned off the firewall, anti virus pgms, reinstalled Outlook, etc.  But still have this issue.

I also physically deleted one of the eMail accounts and added it back in.  Still cannot send eMails via Outlook.

On Sunday night, everything started working again. I thought everything was good to go. But, Monday morning the same issues happened. Can no longer send eMails. The whole day went by and I was not able to send eMails.  THen late Monday night, it started working again.  I woke up this morning, and once again it is not working.

Very frustrating spending 2 days trying different things only to end up failing. Searching the Internet I have seen others who have posted same issue after updating their passwords. They too have not received an answer on how to fix the issue.

Anything left for me to do?

I have the same issue! I am able to login my Xfinity account and check email via Xfinity website, but my third-party software APPLE MAIL keeps asking me the password to login my mailbox.  I tried to delete and add the Comcast email account, and APPLE MAIL still cannot access my Comcast email account.  It's the 3rd day now.

I use Apple Mail and am also having issues since Comcast forced me to change my password. I can receive but not send mail. I spent several hours yesterday on hold with Comcast before speaking with THREE representatives. The Level 3 guy seemed to get it working last night but this morning, I cannot send again from MacMail!

This is exactly what I am going through also. Spent hours on the phone. Things start working at night but fail to work the next morning.  All Xfinity technicians that I have spoke to are trying to blame Outlook.  But, I found that another software package that I use to generate invoice for my customers also stop sending eMails.  It does not even use Outlook. It just uses Comcast credentials.

Xfinity needs to wake up and stop blaming everything on Micorosft. They need to look at the issue more closely.

ATTENTION XFINITY/COMCAST REPS: Stop trying to pass the buck and make this a "IT'S A 3RD PARTY EMAIL CLIENT PROBLEM" when YOUR COMPANY started the problem and all roads lead to the password change and some sort of blockage to passing the new password credentials through to whatever normal ports are set up!

You have now heard from several Outlook and Apple Mail customers who have the problem.

In my case I own several Comcast email accounts and I only changed 1 password. ALL of my emails are working except the 1 I changed 2 days ago. First I was unable to send any mail but did receive it, now nothing. I'm staring at a blank Apple Mail mailbox! YEARS of history gone.

I also spent an hour on the phone today with 2 different reps who couldn't do anything for me because they have no idea what's going on with this issue. I alerted them that it's now documented on this forum which they knew nothing about. WHY?

XFINITY/COMCAST needs to be the one to change whatever is wrong and not make it's customers suffer with hours on the phone with TS Reps who know nothing about this problem whatsoever!

What they do know how to do is ask me if I want to subscribe to Xfinity Mobile! All after alerting us Fees will increase AND not providing us stable services. Why would I switch over?!

I had a text chat with an Xfinity service tech on 12/18/23. Here was his answer to me, cut & pasted from the original: 

I completely understand your concern, however, I would like to inform you, this is an ongoing issue which many customers are facing and our back end team is already working on this concern and most of the emails and password have started working. Please be assure and help me with your best contact number or email to notify you once the issue will be resolved.

This issue is now 4 days old with no end in sight. Apparently, nobody on this thread received a seemingly honest answer I did. My wildest guess is that this issue was caused by upgraded security recently implemented to protect from a reoccurrence of the huge data breach that occurred at Comcast/Xfinity in Oct/Nov. Possibly an unintended consequence of other actions. Possibly intended. Either way, we'll never know. I just want it fixed sooner rather than later. An honest "expected resolution timeline" would save a lot of angst from a lot of customers. Its crippling.  

I have had the same problems.  Recently (yesterday) and intermittently.  Comcast always blames Outlook.  And then "encourages" customers to use the Comcast web based email.  I am convinced the problem is not Outlook, and I do not want to use Comcast webmail.  I believe Comcast does not have enough infrastructure in-place to meet the demand of all the third-party email applications on their mail servers, in particular with the roll-out of the iPhone 15.  Comcast just admitted to a data breach effecting 35.8 million customers!  That is a LOT of customers.  How many of those 35.8 million are using third party email apps like Outlook? 

I have a very similar, and maybe the same, problem.

My wife and I have four Windows 10 machines and four Apple products.  Since we moved last year, we have used legacy Comcast email addresses as is graciously permitted by Comcast.

We are unable to connect to Xfinity mail servers, sometimes incoming and other times outgoing, much of the time.  Either they all work, or they all don't work.  They worked for a while yesterday afternoon and now don't work today.

All machines have worked reliably in the past.   No configuration changes have been made except for the mandatory password change.

We connect using our local network to Spectrum cable (Comcast is not available here.)  Two of the windows machines are hard wired to our router and the others connect via wifi.

Interesting tidbit....

On my Iphone if I connect to the Xfinity servers via Spectrum *cellular* (aka Verizon), I can currently send and receive my comcast.net email.

If I connect via wifi through our router and modem via Spectrum *cable*, I cannot send and receive comcast.net email right now.

Again this has worked fine in the past.  Email configuration in both cases is identical.  Ports and other settings have been verified multiple times.

This would seem to suggest that the problem, in my case at least, is somewhere between the local cable ISP (Spectrum) and the Comcast servers.  The cynical side of me had the thought that Comcast doesn't want smooth connection to its servers via Spectrum, but I doubt this is the case.

This is clearly beyond what the customers of Xfinity, Spectrum, or Microsoft can diagnose and fix on their own.  It's in the best interest of all three (and maybe more) providers to collaborate to quickly and effectively address their joint problem.

Update:

As of 8pm CST, Xfinity and Outlook are playing nicely together.   Emails are coming and going normally.

....for the moment.

I sure wish Xfinity would publish what has been going on.  The longer this remains a mystery, the more credibility Xfinity loses.