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Can't send email - thunderbird

  • 2 replies
  • 1 has this problem
  • 9 views
  • Last reply by diegodad

diegodad
diegodad
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I installed Thunderbird on a new Windows 10 computer. When I try to send email I get this message: Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) mail.twc.com was lost in the middle of the transaction. Try again. I verified with Spectrum that SMTP is correct using port 587. I tried turning off McAfee anti-virus and firewall.

I installed Thunderbird on a new Windows 10 computer. When I try to send email I get this message: Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) mail.twc.com was lost in the middle of the transaction. Try again. I verified with Spectrum that SMTP is correct using port 587. I tried turning off McAfee anti-virus and firewall.

Chosen solution

Have you tried these settings? Outgoing server mail.twc.com on port 587 with Connection security = None, authentication = password, transmitted insecurely and User name = email address.

https://support.mozilla.org/en-US/questions/1161629

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sfhowes
sfhowes
  • Top 25 Contributor
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Chosen Solution

Have you tried these settings? Outgoing server mail.twc.com on port 587 with Connection security = None, authentication = password, transmitted insecurely and User name = email address.

https://support.mozilla.org/en-US/questions/1161629

diegodad
diegodad Question owner
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Thank you, sfhowes. I checked Connection Security on both my new laptop and an older desktop. The laptop is set to SSL/TLS while the desktop uses STARTTLS. I changes the laptop to STARTTLS and now the problem is gone.