yarn error "EACCESS: permission denied, scandir '/home/ubuntu/.config/yarn/link'"

It's likely a unix permission related problem. There is a solution posted on the dev's github page. Try to run the following command

sudo chown -R $USER:$GROUP ~/.npm
sudo chown -R $USER:$GROUP ~/.config

Reference: EACCES: permission denied .config/configstore/bower-github.json #2262

I had this problem as well, I found on another thread that my config folder was owned by root, which created several permissions issues.. I changed owner to my user and this error went away.

See top answer on this thread Unable to access 'git/attributes'