How to add Yahoo calendar ?

These simple steps will show you how to add and synchronise a Yahoo calendar.

Basic authentication / Application specific password

To use Yahoo with OneCalendar, log into your Yahoo account, go to "Account info" / Account security. Then,

if you're using two-step verifcation: generate an app specific password for OneCalendar
if you're not using two-step verification: enable "Allow apps that use less secure sign in"

Settings

User name: Yahoo email address
Password: if you're using two-step verification, your app password generated for OneCalendar; otherwise your Yahoo account password