Yahoo and rest emails also show this type of issue due to some settings or some reasons. No worries, here are some tips to fix this issue as soon as possible.

1. Clear your browser's cache.
2. Update your browser.
3. Restart your computer.
4. Make sure that JavaScript is enabled.
5. Disable browser enhancements.
6. Temporarily disable antivirus, antispyware, and firewall products.
7. See if the Yahoo service works from another computer or mobile device.
8. Reset your browser to default settings.

Resource URL: https://emailspedia.com/yahoo-mail-is-not-working/