Yahoo email account won't add to mail on MacBook

The error message “Unable to connect to server '(null)'” does not identify the specific cause. 

First, sign in to your Yahoo Mail account in Safari to confirm that you can access your email. 

Then open Mail, choose Mail >> Add Account, select Yahoo, and follow the Yahoo sign-in instructions. 

Apple’s instructions for adding an email account are available here: Add and manage email accounts in Mail on Mac. 

Apple also recommends choosing the correct email provider when adding an account: Choose the correct email provider in Mail.

If the same error continues, you can also check whether using a Yahoo app password is appropriate.

Sign in to your Yahoo account in Safari, open Yahoo Account Security, and under External connections, select Create app password. 

Give it a name such as Mac Mail, generate the password, and use the generated password if Mail asks you for a password. 

Yahoo's instructions are available here: Generate and manage third-party app passwords. 

Yahoo explains that app passwords are used by third-party email applications that do not use Yahoo's branded sign-in page. (Yahoo Help)

The message “Unable to connect to server (null)” does not, by itself, identify the cause. Begin by confirming that you can sign in to your Yahoo Mail account in Safari.

If you can, the next step is to check whether an unsuccessful Yahoo account setup is already present on your Mac.

Open Apple menu  >> System Settings >> Internet Accounts. 

If a Yahoo account appears there but was not successfully configured, you can remove it before trying again. 

Apple explains how to add, manage, and remove Internet Accounts here: Use your internet accounts on Mac. (Apple Support)

You can then add the account through Mail >> Add Account or System Settings >> Internet Accounts >> Add Account. 

When Yahoo is available as an account provider, select Yahoo and follow the information requested during the sign-in process. 

Apple documents this procedure here: Add and manage email accounts in Mail on Mac. (Apple Support)

The password you created at Yahoo and named “Mac Mail” is a Yahoo app password. 

It is intended for situations where a third-party email application requires an app-specific password rather than Yahoo's normal sign-in process. 

Therefore, it is best to follow the sign-in method requested when you select Yahoo as the account provider rather than entering the app password unless Yahoo or Mail specifically requests it.

I am in same boat .. all these steps did not work. please guide

I have this same problem and these suggestions don't fix the problem. This is a brand new issue for me after using Yahoo on this same MacBook for a long time. Did something change recently?

I have tried absolutely everything and none of it works. The curious thing for me is that it accepted a different Yahoo email account with no problem.