Can't send email from outlook

I'm back to not being able to send from outlook from my home network.  If I switch to my wifi hotspot, then sending works and I get no errors..

Hi  @rte3424 Thanks for circling back with us about your outlook issue. Is it only Outlook with this issue? Are you able to log into your Xfinity email account and send/emails without an issue?

What is the error message you're seeing with outlook? 

I have the same problem, but it's not just Outlook. This also happens from the iPhone, Android/Samsung email client - any email client. You can go to the email website using a browser and can send and receive just fine. Starting about 8 am PST, emails just hang in Outbox or the email client returns an error. Around 4:30- 5 pm PST, suddenly the problem goes away and it's good until the next day. 

Me too, but I like Outlook.  The problem comes and goes and there is nothing I can do short of giving up the email address that I've had for over 20 years.

Hi there @user_x92ka8. I am sorry to hear you are having troubles with our email through your Outlook application. You are in the right place and we are happy to assist you. Are you still having this issue? 

Good for you. I'm not so fortunate. Yesterday, at about 4 pm PT, the emails started flowing again from my comcast.net account. But this morning - no luck - back to "errors in sending email". I am convinced there's some kind of timer set for my comcast.net accounts - no outgoing emails from this guy's email clients using Spectrum internet between the hours of...6 am to 4 pm PT, maybe. Very frustrating.

I'm convinced that comcast.net is rejecting email send requests from my network (Spectrum - the only choice in Palm Springs, CA) during certain times of the day. The ONLY time an email sits in my outbox, whether from Outlook on my Windows PC, or my phone using Android/Samsung email client, or our iPhone or iPad using some Apple email client, is when any of these devices are on our Spectrum ISP network - and then only at certain times of the day, like 7 am to 4 pm Pacific time. When any of these devices ae on any other network, the emails go thru just fine. This MUST be something in Comcast/Xfinity that is preventing email smtp send requests thru port 465 - but only at certain times of the day. Sorry I keep repeating myself, but this problem goes away around 4-5:00 pm Pacific time. I am at a loss as to what to do since comcast/Xfinity refuses to acknowledge an issue.

Have you tried switching from port 465 to port 587? Our guidance online outlines 2 ports as the options for the configuration of outgoing mail to be set on. After reconfiguration, you'll need to update the encryption settings of your outgoing mail server from non-encrypted to encrypted settings. If you don't adjust your email settings, you'll still receive emails, but not be able to send emails after the non-encrypted email settings are blocked.

Hello - thanks, I did try to switch the port to 587 but it was during a period when I couldn't send emails, and I received an error. Today everything is working fine and I did not touch a thing.  My theory is that the anti-spam tools and processes Xfinity has in place may be responsible for preventing my emails from going out if it detects that the email send request is from the Spectrum network, which may be a network that has been identified as the sending network of spoofed spam emails. The Xfinity process stops emails from (my) comcast.net address from being sent, but only for some period of time. IN every case my email clients can start sending emails in the evening (Pacific time) - then the next morning, I can't send any emails again while on Spectrum network...until early evening.  But today is different - everything is working fine.

I'm not making this up ;-).

Any checking you could do to see if Xfinity is preventing emails during the day from being send using a cmcast.net address from Spectrum network would be helpful. Maybe my email address has been compromised in some way (I've changed the password many times) and Xfinity puts the brakes on outgoing emails.

I have the same problem. Exactly. The ability to send emails from Outlook, and sometimes from my iphone, goes in and out. I have a Spectrum network also, but have not had this problem in the past. It just started about 2 weeks ago. I have followed all of the advice above, and everything I can find to do on other sites, but am not able to fix this irritating issue. Is there an Xfinity tech support number for email malfunctions such as this?  

Thanks

@user_1ij10x​ 

The error message I receive on Outlook is 

- Sending' reported error (0x800CCC0F) : 'The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).'

Error when sending from outlook

@Anon636749​ sadly, I have not found a solution other than to stop using comcast.net email addresses OR use another network - like my phone hotspot - so that I am not sending emails from my comcast.net email addresses from my Spectrum ISP network. This problem only happens when sending emails from any email client while on Spectrum's network using any of my comcast.net email addresses (we have 3). I am speculating that Xfinity's anti-spam tools are the culprit. Here's my theory - Xfinity is trying to detect patterns of spoofed emails using comcast.net addresses originating from certain networks, like Spectrum (or Charter). When Xfinity detects am email being sent via smtp.comcast.net, it prevents the request from the email client from getting thru to smtp.comcst.net because it thinks it's spam.

But - this only happens during the day. At night, without any configuration changes on the email client side, the emails start flowing again and all 3 email clients can send emails from their respective comcast.net emails - until the next morning.

I've been thru an exhaustive search for any problems on the Spectrum end and came up with nothing. we strongly believe this issue is on the Xfinity side when it detects emails being sent from Spectrum network. 

I would like to email you directly and compare notes to see if we can determine any more details, but unfortunately, I can't until tonight, when this problem disappears for the evening ;-). 

@Anon636749​ If you would be willing to trade messages directly, please email me at [Edited: "Personal Information"]. I can receive emails anytime during the day or night - I just can't send them during the day.

@Anon636749 Please send me a DM with the email address you're having an issue with, and we'll take a look at the detailed logs.  Click on my name, and find the "three dot menu" and choose "Send Message".

I have found a work-around.  If I connect to my VPN service, then I am able to send from outlook using my comcast account.  Hopefully this thread keeps getting bigger and someone at Comcast will notice and look into it.

@kvollman and @rte3424 Please send me a DM with your usernames.  Also, look at the note from user_x92ka8 below this.  A device with an old password may be having an impact here.  But please, send me a DM, and I can confirm this for you.

Hello @kvollman, thanks for reaching out to let us know that you are also having trouble sending mail from Outlook. If you haven't already, can you please try removing your comcast email from Outlook, and then re-add it by following the Outlook steps here: https://www.xfinity.com/support/articles/email-client-programs-with-xfinity-email. 

That's not my issue.  I can receive all day, on all devices, I just can't always send.  Can't be the password because sometimes I can send, depending on the time of day or if I get off my home network.

Yes, those were my symptoms. In my case, though, I had the correct password in my "regular" email client (Outlook) but I had another email client (Windows Mail) that was running -unintentionally- and that email client did NOT have the correct password. That was the cause of my problem. Check all the devices that might have any of your comcast.net email addresses configured and make sure something is not running unintentionally that may have an old password configured. That could cause the send problem for all your other email clients on your "regular" network.

@LR31​ Please send me a DM with your username.  We'll take a look at the detailed logs.

Same with me. It went back to normal and I thought this issue was solved. Unfortunately, I have the same issue. No email can be sent during the day.  

XfinityAlex, have you found any solution???

This is the error message I get.

Task  Sending' reported error (0x800CCC67) : '  The server responded: 421 resomta-c2p-555481.sys.comcast.net resomta-c2p-555481.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available'

I will try to direct message. Problem has come back and I can no longer send from Outlook to Comcast.

Account is  in my wife's name. And I don't know how to find DM.

@Anon636749 here is how you can send us a direct message. 

(Full credit to @BruceW for this excellent explanation!) 

"Search for Xfinity Support" won't work. To send a "Direct Messaging" message to Xfinity Support:

• Click "Sign In" if necessary

• Click the "Direct Messaging" icon or https://forums.xfinity.com/direct-messaging

• Click the "New message" (pencil and paper) icon

• The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there

•  - As you are typing a drop-down list appears. Select "Xfinity Support" from that list

•  - An "Xfinity Support" graphic replaces the "To:" line

• Type your message in the text area near the bottom of the window

• Press Enter to send it

See https://forums.xfinity.com/conversations/email/cant-create-a-new-email-address/605e52b726aa974d63032d02?commentId=606107ea738c7f46a02b830e

@magnuson_mn​ A quick add to my post above. Norton allows you to configure split tunneling for your VPN and add exclusions so that apps you specify won't go through the VPN.  So, I've configured Outlook.exe to be excluded from the VPN which allows me to have the VPN up for everything else.  In case that is helpful for anyone else.  

@user_0ozxjl​ This is from the O365 Webmail? or the Desktop Outlook?  There's no error given?