When I try to download this modpack in twitch on a mac, this message pops up:
"Unable to get Addon: Galactic Science (232015) - File ID: 2761972"

Could someone help me with this issue or tell me another way to play this pack?

I'm unable to reproduce this issue. Please try whitelisting the twitch launcher from your anti virus program.

Otherwise you will have to contact the CurseForge support here: https://twitchpartnerships.force.com/curseforge/s/contactsupport