error with online servers

So yes, I don't know why but I can't connect to every minecraft server. The Internet, I have a version, it starts normally online, I have the current version of Java, all updated internet works. I can't play on servers, I don't know why, and I didn't buy minecraft so I wouldn't play. I have never tried it before, but it certainly does not apply to my internet. I am asking for help or a refund for the game.
Anyone know how can i fix it?
Thank you in advance