Looks like their TLS/SSL certificate expired a couple days ago. Happens sometimes, especially with sites that don't have an experienced web admin. The webarchive link Gowithit posted works to read the page.
The calls themselves can still be played and downloaded here:
[ + ] Needmorepopcorn
[ - ] Needmorepopcorn 0 points 1.9 yearsJul 10, 2023 01:28:08 ago (+0/-0)*
https://archive.org/details/LasVegasShooting2017/2019+05+10+-+Las+Vegas+Shooting%3B+If+Paddock+is+Dead%2C+Who+is+Firing+These+Shots+at+Midnight%5BQ%5D+-+%5BYT+-+PSyD72B5e68%5D.mp4
I listened to all of them.
My favorite is the fucking black guy in a field calling in to give his location to not get shot.
There is also a call from an off duty and he report suspicious people / Short arabs with tiny hats.
[ + ] GloryBeckons
[ - ] GloryBeckons 2 points 1.9 yearsJul 9, 2023 21:25:47 ago (+2/-0)
The calls themselves can still be played and downloaded here:
https://archive.org/details/LasVegasShooting911Calls/
[ + ] Gowithit
[ - ] Gowithit 1 point 1.9 yearsJul 9, 2023 21:34:11 ago (+1/-0)
[ + ] SignedUp
[ - ] SignedUp 2 points 1.9 yearsJul 9, 2023 21:23:30 ago (+2/-0)
[ + ] Gowithit
[ - ] Gowithit 1 point 1.9 yearsJul 9, 2023 20:43:58 ago (+1/-0)