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Thunderbird v115.9.0 (32-bit) not sending Yahoo email

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  • Last reply by Matt

fph1
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Hello. Cox Communication is our ISP. Cox recently migrated all cox.net email accounts to Yahoo! mail. Yahoo! mail now works fine on Apple devices -- iPhones and iPads. Yahoo! mail can be received on Thunderbird but not sent. The error message is: "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.mail.yahoo.com was lost in the middle of the transaction. Try again." MAIL PROVIDER: Yahoo! ISP: Cox Communications FIREWALL/ANTIVIRUS SOFTWARE: BitDefender Premium/Total Security Build 27.0.30.140 OPERATING SYSTEM: Windows 10 Business; Version 22H2; OS Build 19045.4170 THUNDERBIRD VERSION: 115.9.0 (32-bit) SMTP SETTINGS: SERVER NAME: smtp.mail.yahoo.com PORT: 587 and also have repeatedly tried using port 465 CONNECTION SECURITY: SSL/TLS AUTHENTICATION METHOD: have tried both Normal Password and OAuth2 CONNECTION SECURITY: SSL/TLS USER NAME: have left blank (as I have multiple email user names) and even tried using a single account name

Hello. Cox Communication is our ISP. Cox recently migrated all cox.net email accounts to Yahoo! mail. Yahoo! mail now works fine on Apple devices -- iPhones and iPads. Yahoo! mail can be received on Thunderbird but not sent. The error message is: "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.mail.yahoo.com was lost in the middle of the transaction. Try again." MAIL PROVIDER: Yahoo! ISP: Cox Communications FIREWALL/ANTIVIRUS SOFTWARE: BitDefender Premium/Total Security Build 27.0.30.140 OPERATING SYSTEM: Windows 10 Business; Version 22H2; OS Build 19045.4170 THUNDERBIRD VERSION: 115.9.0 (32-bit) SMTP SETTINGS: SERVER NAME: smtp.mail.yahoo.com PORT: 587 and also have repeatedly tried using port 465 CONNECTION SECURITY: SSL/TLS AUTHENTICATION METHOD: have tried both Normal Password and OAuth2 CONNECTION SECURITY: SSL/TLS USER NAME: have left blank (as I have multiple email user names) and even tried using a single account name

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Matt
Matt
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FIREWALL/ANTIVIRUS SOFTWARE: BitDefender Premium/Total Security Build 27.0.30.140

Just disable that and I think the issue will just not exist anymore.

Just to be clear, email connections are not guess work. What will work is determined by the email provider (Yahoo in this instance) and they publish the settings you need to use.

The yahoo settings are stated by then as; https://help.yahoo.com/kb/SLN4724.html

Outgoing Mail (SMTP) Server 

   Server - smtp.mail.yahoo.com
   Port - 465 or 587
   Requires SSL - Yes
   Requires TLS - Yes (if available)
   Requires authentication - Yes

Your login info 

   Email address - Your full email address ([email protected])
   Password - Generate App Password
   Requires authentication - Yes

While Yahoo still advertise as accepting application passwords (which you make no specific mention of using in your attempts with a password), they should be avoided as yahoo's preferred method of authentication is oAuth and has been for a number of years for both incoming and outgoing mail.

The oAuth initial authentication flow of web pages is the only time a yahoo password will work with authenticating to a yahoo email account, despite it working on their website. oAuth once authorized uses tokens and password authentication uses app passwords generated by Yahoo on their web site.

Note SSL/TLS. Yahoo makes is sound like two things. SSL came first, TLS replaced it and therefore Thunderbird lists it as SSL/TLS, despite SSL being completely obsolete for years now (Deprecated 2015). Having been replaced by TLS 1 in 1999. Yes, last century. The internet moves very slowly in the security space as some provides offer the least possible for a price.