Can't install on MacOS HighSierra

[davo301]

My ruby version is "2.3.7p456"
When I type "gem install generamba" I get the following error

ERROR: While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /Library/Ruby/Gems/2.3.0 directory.

[Leonif]

sudo gem install generamba

[davo301]

sudo gem install generamba

Doesn't work. Again issue with access, but logged in with admin user.

[Leonif]

I installed on to Mojave. Try to reinstall your OS or install Mojave

[shengyang998]

try gem install generamba -n /usr/local
or disable the SIP

[st-small]

I have a similar problem on Catalina 10.15.6 and fixed it using these commands:

brew update && brew upgrade
brew doctor