Many factors are responsible for creating hindrances in the proper functioning of Yahoo Mail on your computer. If your Yahoo won't load, the reasons can be server outage of Yahoo Mail, browser's incompatibility, an old version of your browser, unwanted jam of caches and cookies, faulty or improper computer settings, availability of malware in your computer, slow internet network connection, third-party antivirus or firewall interfering blocking your Yahoo Mail access. These are all the various reasons that are responsible for causing problems while accessing your Yahoo Mail account and stopping you from using the common functionality of Yahoo.