Hey guys, I would seek help from anyone, whenever I try to log in it says "Failed to verify username", what's the fix for that?

Hello fellow community, i'm m7mdsoliman, a simple gamer who got suggested to download Minecraft by one of his friends, I liked the game very much, got used to it quickly, and when I found out that there's such servers like roleplay and this online, I went out searching for what I kinda like -...