Check to see if the internet on your Mac is switched On or not. If the launch of Yahoo! Mail fails, and it does not connect, the first thing that should check is your network connection. Good internet is essential to connect with Yahoo! Mail as it is an online email service. You can go through the following solutions to fix Yahoo! Mail Not working on Mac: 1. Mail issues happen due to invalid settings or if there is something wrong with your Mail account. Yahoo Mail Not Working on Mac? 10 Solutions:
Some sort of Malicious Software or virus might be preventing access to Yahoo! Mail.Yahoo! Mail server might be down that would cause the connection issue.Your account has been blocked or its security has been compromised.There might be some interference with a third party software installed in your Mac.
If you use your mouse, you may miss out on some of the vital code needed to make your signature work correctly. Don't use your mouse, only use Ctrl + A (hold the Ctrl button and press A at the same time) to select all of your email signature. More than likely, you have used your mouse to highlight the html email signature file in the browser. My email signature doesn't look right when I paste it
In order for your email signature to work in both the desktop and iPhone/iPad app versions of Yahoo Mail, you will need to reduce your email signature to under 10,000 characters and install it directly into Yahoo Mail's signature settings. The way the browser extension works is that it injects the HTML from your email signature directly into the browser page, it does not save it to Yahoo Mail's settings. If I use the browser extension, will my email signature work with the Yahoo Mail iPhone/iPad app? If you do, please see our Web Browser Extension instructions to bypass the character limit restriction. This has been removed and you shouldn't experience any issues when installing your email signature. Yahoo Mail used to apply a character limit restriction to their settings when installing email signatures. I get an error saying my email signature is too long. If you have tried our Step-by-Step Guide or Browser Extension instructions for installing your email signature Yahoo Mail and you run into any issues, please read through this troubleshooting guide before contacting Support for further help.