Moving Sims 4 to external drive

I am desperate for some input, I have tried uninstalling and reinstalling TS4 to my new hardrive at least 5 times, I have uninstalled and reinstalled the ea app and I have chatted with ea helpdesk and every time I try to redownload my expansion packs this message pops up. I have no mods, I am a completely vanilla player and I use a Macbook air with a newly bought external harddrive. Please help <3