Cannot obfuscate dll

Question

I'm using Confuserex for obfuscate a dll, I compiled it using visual studio, then I opened ConfuserEx GUI, dropped the dll on the project tab, and then in the settings tab I added a new rule with the maximum preset.

After that, I click on "Protect" button available on the protect tab, and when I open the "obfuscated" dll with dotpeek a disassmbler software provided by intellij I can read all the method and class as the dll is never obfuscated.

This does not happen with .exe only with dll, what I'm doing wrong?

UPDATE

example structure:

namespace Test
{
    public class Foo<T> : ViewModel
    {

        public Example() { }
    }
}

Answer 1

From the answer from this Issue. https://github.com/yck1509/ConfuserEx/issues/573

n-dimens answer : "it is because the dll and pdb in the same folder. In this case, dotPeek opens the source code instead of the decompiled"

You can just rename or remove the file .pdb file. Then in dotPeek can not decompile it.