Cubase 11 pro, cant install any content on my mbp

hi guys,
I’ve a serious Prob. on my mac: I can’t install any content on my MBP (OS versio:10.14.6).
When I install any contents, it shows:“Steinberg Library Manager privileged helper has wrong version (-1-1). Failed to establish privileged helper! Please get the latest Steinberg Library Manager and reinstall!”.
I’ve tried all version of "Steinberg Library Manager"that I can dowload from the official website, but the Prob. still there.
and some friends said I need to check my “SIP” on my MBP, I’ve tried disable it and Enable ti , both not working .
but my iMac(OS version:10.15.6) works totally fine !
Pls help me ~!!!
thx alot!!!