I had this same problem. The Community Edition is free, but you have to sign into your Microsoft account to use it more than 30 days. Go to "https://account.microsoft.com/about" and signup for an account. It's free. When you complete the process, you can sign into Visual Studio using the same email address.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…