The href attribute is required for an anchor to be keyboard accessible. code example

Example 1: React site warning: The href attribute requires a valid address. Provide a valid, navigable address as the href value jsx-a11y/anchor-is-valid

// just change 
href="#" // -> to correct url 
Example: 
href="https://learn-tech-tips.blogspot.com/"

Example 2: The href attribute is required for an anchor to be keyboard accessible.

href="/#" to replace href="#"