If 2-Step Verification/2 Factor is turned on/in use, you must create an app password for the printer to use. (This is _not_ a Passkey).
Select Generate app password or Generate and manage app passwords
Enter your app's name in the text field (suggestion: KYOCERA printer)
Select Generate password
Copy the code as it will be used below in Step 5., 3.
Select Done
... on the printer's web page
Set SMTP Protocol to On
Set SMTP Port Number to 587
Set SMTP Server Name to smtp.mail.yahoo.com
Set SMTP Server Timeout to 180
Set Authentication Protocol to On
Set Authentication as to Other
Input the <email address> in Login User Name
Input/Paste in the password or app password in Login Password
The maximum length of the Login Password is 64 characters
Set SMTP Security to STARTTLS
Set Sender Address to the _same_ email address as used for the Login User Name
The maximum length of the sender address is 128 characters
Set SMTP Authentication and Sender Address to Use System Settings
Only some models have this setting
Additional information