The Yahoo email settings are the same in both ClientBase Windows and ClientBase Online.
In ClientBase Windows:
If you are a user, go to Utilities > My Login > Email Settings.
If you are a database administrator, go to Utilities >User Logins > User List. Double-click on the user and select the Email Settings tab.
In ClientBase Online:
If you are a user, go to Tools > My Login > Email Settings.
If you are a database administrator, go to Tools > Settings > User Logins. Click on the user and select the Email Settings tab.
Go to the Security section in their Yahoo account and make sure Two step verification must be turned on. Here is how:
Log into the user’s Yahoo account and select the Google Apps icon located in the upper right hand corner of the screen. Next, select Account.
On the left hand side, select Account Security.
Move down to '2-Step Verification. Two step verification must be turned on.
After you turn on 2-Step Verification, you will be able to create an app password for ClientBase. Move down the page slightly for App Password. Select Generate app password.
Enter an App name like CBO or CBW and select Generate Password.
Copy the app password, and paste it in the password field in CBW or CBO. If you are testing in CBW, if the test is successful, don’t forget to go to Utilities/My Login to paste in the Email Settings tab to change permanently.