Hello toomuchcouchgrass, you say that you use your Blackberry to access Yahoo emails when away but how do you access your emails from home? The email client (app) you have set up to access Yahoo email from home may not meet modern/Yahoo's security standards. When you access emails using older apps, the account information, including passwords, is sent over the network. Yahoo deem this transfer of sensitive information to be insecure using older apps. However, when Yahoo send you an email, they don't know which computer/mobile you will use to open it, so the email may not apply to all the apps you use. Your Blackberry may not be the problem. Yahoo can see what settings various apps on all devices (including home computers, tablets and mobiles) are using to access emails and will block those they believe to be insecure. You can log into your Yahoo account and allow apps that use less secure sign in. Given the huge data breach that Yahoo have recently had to acknowledge, they were duty bound to tighten up security.
Which posters did you have on your wall in your teens
Venice and the river Po, a virtual cruise