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Visitor

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8 Messages

Thu, Mar 25, 2021 5:56 PM

Outlook 2016 for Mac unable to make secure connection to server

I have been running Outlook for the Mac for 5 years and this month I just started getting this error that Outlook can no longer make a secure connection to the  smtp.comcast.net server.     I then get asked to accept a COMODO certificate and I can again work but that connection is not secure and Outlook will not let me send anything labeled confidential.  Any words of advice will be appreciated.

Responses

Visitor

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8 Messages

3 m ago

This is what I get when I try to do a send and receive .

Official Employee

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215 Messages

Hey there ! Thanks for reaching out. Have you confirmed all the settings are correct for your clientt? https://comca.st/3dxtGR5

 

  • Incoming Mail Server Name: imap.comcast.net
  • Incoming Mail Server Port Number:
    • Recommended: 993 with SSL ON
    • Only if Needed: 143 with SSL ON
  • Outgoing Mail Server Name: smtp.comcast.net
  • Outgoing Mail Server Port Number:
    • Recommended: 587 (SMTP)
    • Only if Needed: 465 (SMTPS)
  • SSL Encryption: checked
  • Authentication: XFINITY username and password required

(edited)

Visitor

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8 Messages

No I was using mail.comcast.net and smtp.comcast.net.  I will try the addresses you listed. 

Visitor

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8 Messages

Exact same error Connection to the server failed or was dropped.

Visitor

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8 Messages

one caveat if the document has no attachments or the email is not listed as confidential it sends fine.  Just outlook keeps telling me that a secure connection could not be made.

Visitor

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8 Messages

3 m ago

Thank you both for the suggestions. Unfortunately, neither of these solutions helped.  My Comcast settings are exactly what they are supposed to be.  From what I can tell Comcast did something to the server side certificate that is causing this.   As I said earlier.  I have been using outlook for years with my Comcast email. This just started last week.

Visitor

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8 Messages

2 m ago

OK so after contacting Microsoft support ( they were great). We found out that Norton 360 had a major issue with Big Sur and Outlook.  Norton is working on it.   Thanks for the suggestion to contact MS support.

New Poster

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2 Messages

1 m ago

I have the same issue -- MS Outlook support say Comcast needs to look into this -- it seems to be an issue with many. The connection error code is 16997 & 17099. Apple support also indicated it seems to be a Comcast configuration issue. I have reported this to Comcast Support, but have not heard back.

Again

Expert

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25.8K Messages

@finkel

Did you check the link I provided above to see if it applied to you?

Visitor

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8 Messages

@finkel   open up norton and disable the firewall and see if the problem goes away.

New Poster

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2 Messages

@user_056e0a  Thank you for your post!  I was having the same issue.  Disabling Norton firewall did indeed resolve my problem.  Hopefully Norton and MS can get together and resolve this.

(edited)

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