Wordpress in Docker doesn't connect to the Internet

Hi all,
My wordpress inside a container doesn’t connect to the Internet, so if I i.e. do an action like install a plugin, I receive an error like:

“Installation failed: An unexpected error occurred. Something may be wrong with WordPress.org or this server’s configuration. If you continue to have problems, please try the support forums.”.

Cam someone help me? I think it need some network options… I used docker instead of docker-compose, and run the instances with the following commands:

docker run --name mysql -p 3306:3306 -e MYSQL_ROOT_PASSWORD=password -d mysql:5.7

docker run --name wordpress --link mysql -p 80:80 -d wordpress

It works, but wordpress don’t reach Internet.
I have a Proxy configured inside Docker, if it can be useful.
Thank you very much.