When you use homebrew to install php 7.1 it will cleverly install php-fpm which listens on port 9000. This is the default port for xdebug, so if you want to debug php scripts in a lando container, you will have some challenges.
If you've installed php 7.1 with homebrew, it listens on port 9000 so you will need to change the containers php.ini port specification to another port. e.g.
Then tell phpstorm to listen on port 9001