Hello.
There is an admin option to control this, under "Security-->Site Policies" (searching for "cron" is an easy way to get there, as it also limits the results to the matching options):
"Cron execution via command line only"
Is disabled by default, at least in 19.x, but I think it may be the culprit.
Of course, you can run the cron.php via command line using php.exe cli (there is plenty of info about this, and it is quite easy), but I think the former will be easier to begin with, and is a better way to see the cron log.
Hope this helps.
Greetings.