IMAP issues with Comcast since Nov 9th

Same problem with IMAP from Outlook with intermittent server connection error; connection on smtp for outbound is fine.  IMAP didn't work for two days on one Win10/Office2021 PC and then suddenly downloaded and worked for 24 hours but not connecting again today for more than 6 hours;  Just now suddenly working again.  Very similar problem with Android cell; did not work for a couple of days and then suddenly downloading messages but quit again at 12:15AM today and still not connecting for inbound messages.  One other Win11/Office 2021 PC consistently works upload and download.  All settings are correct and have not been changed.   

I had to switch to STARTTLS and port 143 to get it to allow me to add to Outlook Classic.  
Today, I was able to go back and change it back to SSL/TLS and port 993 and it continued working. 

This seems to be clearly something on the Comcast side.

And like that, with no explanation other than 4/5 days have gone by, it just works again.  If we're on "time out" punishments, I'd be nice to know that and not have to keep trying to get a connection that'll never materialize for another 5 days...

We know who's to blame, it'd just be nice they admit error..

things were working.  Now I get the error "your server does not support the connection encryption type you have specified.  Try changing your encryption method."   

I've tried all various encryption methods.  Note:  This is for Outlook Classic 365.

Any ideas.  This is the yahoo mail   comcast account

Here we go again.  After 5 days of everything working,  imap on multiple accounts doesn't download and just sits with finally an error "cannot connect to server contact server administrator or ISP".  Nothing wrong on this end with technology or ISP.    Last synchronization on Android shows 11PM yesterday.  Download works on one Win11 PC but same account does not download on Android or other PC using Outlook 2021.  

Hey folks, 

I'm going to ask that if you're seeing an issue today (Dec 18th, 2025), could you please DM me some details about your configuration?  (Do NOT put it in a reply here, it will get flagged by a moderator for containing private information)

UserID(s) Impacted:
ISP or Mobile Carrier:
Email Client:
Operating System:

IP Addresses from whatismyipaddress.com (IPv4 and IPv6):
Knowningly using VPN or other Anonymity service: Y/N
Other details:



The "other details" could be something like:
* Mobile works on wifi, not on cellular
* Desktop is fine, mobile is not
* Doesn't work on VPN, works when disabled

* One user works, other user does not

Thanks folks.  I know this is frustrating, and we are working to find the best solution here.

I’ve been having the same issue with email on my iPhone for a couple weeks. Pops up with a prompt to re enter my password. And it pops up a few seconds after I enter it. 

No issues on my desktop computer. I’ve deleted and reinstalled the account on my phone but that didn’t fix it. 

I’m not 100% positive, but I think I’m still getting email on my iPhone despite the issue . Pretty annoying!

I had the same problem also with the Xfinity switch over to Yahoo servers. The problem is you probably updated to the New Outlook.

If you Google Classic outlook and download it from Microsoft then run that and setup the account manually then put in the server setting listed below:

• Incoming Mail Server: imap.mail.yahoo.com.
• Incoming Mail Port: 993.
• Tick Use IMAP.
• Outgoing Mail Server: smtp.mail.yahoo.com.
• Incoming Mail Port: 465 or 587.

Then make sure to check the Secure Password Authentication boxes for incoming and out going.

My family has 4 email accounts with Xfinity/Comcast and I had problems for two weeks with the New Outlook and spoke with Microsoft support, Yahoo Email support and Comcast Email support and all were clueless. After I looked around online I found that there is a major problem with Yahoo Mail Servers and the New Outlook as far as compatibility for security settings go.

After two days of syncing with the yahoo servers I clicked on the upgrade to the new outlook in the top right of outlook classic and everything switched over just fine then but I had to start off in Outlook Classic.

Hope this helps

• Third-Party Access Toggle: A security feature in Xfinity webmail often blocks third-party apps (Outlook, Apple Mail) by default. You must explicitly turn on "Third Party Access Security" in your webmail settings.
• IP Address Blacklisting: Some users report that Comcast temporarily blacklists IP addresses, which stops email client connections (IMAP) while webmail remains functional.
• Network Routing Issues: Some users have suspected network routing misconfigurations or peering issues between providers (e.g., AT&T, CenturyLink) and Comcast’s network.
• Migrational Changes: Ongoing migrations to newer email platforms can create issues that require users to re-add accounts to refresh security certificates.
• Outdated Server Settings: Users must ensure they are using the correct settings:
  • Incoming: imap.comcast.net (Port 993, SSL) or pop3.comcast.net (Port 995).
  • Outgoing: smtp.comcast.net (Port 465 or 587). 

1. Check Third-Party Access: Log into Xfinity Webmail, go to Settings > Security, and ensure "Third Party Access Security" is enabled.
2. Remove and Re-add Account: Delete your account from the app (phone/desktop) and add it back to update security certificates.
3. Check Password: If the app still fails, reset your password via the Xfinity website.
4. Try a VPN: If the issue is an IP blacklist, a VPN or switching to mobile data might bypass the restriction. 

I have also been having this problem. Comcast mail works on my Mac desktop and on web browsers. I tried deleting it and reinstalling under various providers including Yahoo! and "other". Nothing was working. Today I tried again; When I chose "Yahoo" and entered Comcast email and password, I got a message that a very old defunct yahoo email was associated with my Comcast account. This was related to an old Pacbell.net account! Pacbell.net integrated with Yahoo and then later became Comcast, now Xfinity. It asked if I wanted to keep the defunct Yahoo email associated with the Comcast account and I said no. It deleted it and then was able to set up a new Comcast mail account with just the email and password. And now it works.

Not sure if anyone else has an old Pacbell.net or Yahoo account that is somehow associated with your Comcast account, but deleting this associated old email may help. Boy this harkens back to the dark ages,