by Ken Task.
Uhhhhh ... one servers settings may not apply to all servers ... all platforms ... I don't do Windows anymore. ;)
Config of PHP is a lot to look over ... however, in general, the place to look is in your web service logs or DB error logs (if you keep those).
If you see, in those logs, 'server has gone away', its usually due to max_packet_allowed default settings are too low.
See: https://dev.mysql.com/doc/refman/5.7/en/packet-too-large.html
That's a MySQL setting not a PHP setting.
The other place to look and watch the next time you try that large course is moodledata/backup/temp/
That's the directory Moodle uses to build a backup.
And if you turn on debugging while making a backup of that large course, Moodle might be able to provide more specific information as to error.
'spirit of sharing', Ken