I was getting this error using xampp to run an apache server and wanted to explain how I solved it. The error is pretty self explanatory once you know the solution.
Here's the solution:
Enable the intl
extension in the php.ini
file.
Under Apache, click config.
Click php.ini
.
ctrl + f to search intl
to find the extension.
Remove the semi-colon to enable the extension. (This is something that wasn't self explanatory to me at first).
Save the file. Restart your apache server in xampp. The error should now be resolved.