To add to the great advice...
Mac's Mail App is not as modern as iOS's Mail app, Many eMail providers now require a separate App Password different from your eMail password…
Yahoo has gone to this too...
https://help.yahoo.com/kb/access-yahoo-mail-third-party-apps-sln15241.html
randomuser1001
User level:
Level 1
16 points
Posted on Oct 21, 2023 8:32 AM
Solved. In Mac Mail - Go to Add Account and Select "Other". When prompted for email / password - enter your yahoo email address. For password - go to Yahoo Security Page (https://login.yahoo.com/myaccount/security/) and Generate App Key. (Generate and manage app passwords) Use this 16 character code as password.
Cox for Apple Mail…
https://forums.cox.com/discussions/internet/using-yahoo-email-in-mac-os-mail-app/151730
Yahoo cure, thanks to tekkaman65535…
yahoo mail failed to authenticate - Apple Community
yahoo mail failed to authenticate - Apple Community
tekkaman65535 Posted on Aug 9, 2023 10:20 AM
I found a solution for this.
- Delete your Yahoo! account from Internet Accounts.
- Go to your Yahoo! account in your browser.
- Click on your account on the top right.
- Click Security.
- Click Generate and manage app passwords.
- Enter "Mail" when prompted for an App.
- Copy the password Yahoo creates.
- On your Mac, go to System Preferences > Internet Accounts.
- Instead of clicking Yahoo!, click Add Other Account.
- Click @ Mail account.
- Enter your Yahoo! email address and paste the app password you just generated on the Yahoo! website.
This worked for me and I now have my Yahoo! emails actively coming into the Mail app on my Mac.
https://discussions.apple.com/thread/254879377?answerId=260539218022&sortBy=oldest_first#260539218022
Yahoo App password…
Generate and manage third-party app passwords
Some older, third-party email apps (that do not use our Yahoo branded sign in page) require you to enter a single password for login credentials. To access your Yahoo Mail account on these apps, you'll need to generate and use an app password. An app password is a long, randomly generated code that gives a non-Yahoo app permission to access your Yahoo account. You’ll only need to provide this code once to sign in to your third-party email app.
https://help.yahoo.com/kb/access-yahoo-mail-third-party-apps-sln15241.html
Most likely biggest factor is using Other in Mail setup, then using a Browser that doesn’t have Yahoo PW stored init to get the App PW.
https://discussions.apple.com/thread/255004776
Using app passwords with apps that don't support two-step verification (microsoft.com)