Uncaught SyntaxError: Unexpected token '.' inside scss file

1. I was defining the mix file in the css using script tag

2. I was getting the same error because i just used the property of css by 
defining the same styles to 2 element class in scss file. 
Example : .login-box, .register-box{ width: auto }

There are two solutions : 
1. make seperate styles for both elements Like : 
.login-box{ width: auto }
.register-box{ width: auto }

2. Or you can use the scss property 
div, h2, p {
    &.class1 {}
}