Practical advice from a non-social person that forgets names - make notes, even 15 seconds after you meet the person if possible. The name, along with a quick note about where you met them, a feature that stuck out about them, a conversation you had with them, etc. Another thing that helps if you are not great at socializing on the fly (like me), is having pre-planned conversation pieces for people you might meet at a venue, or on the elevator at work. This will help add to the notes. Dittys sometimes work - like if the person's name is Brian and they have long hair - "Long haired Brian". Sounds goofy, but it really does work. Then every time you see that person, you call them by their name to help make it stick.
And if all fails, a "What up DUDE!" always works well too.
Now if you have a brain issue or something, I understand. But as a normal, healthy person, if we aren't making even the smallest effort to remember names, even the non-important ones, then we are more than likely the problem hah!