I found some inconsistency between last PHP 8.0 version and packages in my Laravel project. After downgrade to PHP 7.4 suddenly a class NumberFormatter throws a fatal error.
Fatal error: Class 'NumberFormatter' not found
At first I thought there was a problem with the Laravel Excel package.
But the cause was quite trivial. You just need to enable extension in php.ini by uncommenting one line:
extension=intl
And... It works.