It is important to install the correct Edge WebDriver version as the Edge version installed on your system.
In order to learn the Edge version on your system, please open Settings and more (...) menu from the top right corner of the browser, choose Help and feedback, and then choose About Microsoft Edge.
The popup window will show the current Firefox version on your system.
Now go to the Edge WebDriver downloads page at developer.microsoft.com and download the 64-bit version.
Download the Edge WebDriver for your operating system and uncompress the zip file. The zip files content will be just one binary file msedgedriver for Mac or msedgedriver.exe for Windows.
For Mac you can place this file into /usr/local/bin and for Windows you can place this file in a folder that is currently in your Path.