While using Brizy (WordPress Version), you will find that the Form generates a Success Notification, you can utilize the custom CSS snippet below to automatically hide it

custom.css

.brz-form__alert.brz-form__alert--success {
    -moz-animation: cssAnimation 0s ease-in 7s forwards;
    /* Firefox */
    -webkit-animation: cssAnimation 0s ease-in 7s forwards;
    /* Safari and Chrome */
    -o-animation: cssAnimation 0s ease-in 5s forwards;
    /* Opera */
    animation: cssAnimation 0s ease-in 5s forwards;
    -webkit-animation-fill-mode: forwards;
    animation-fill-mode: forwards;
}
@keyframes cssAnimation {
    to {
        width:0;
        height:0;
        overflow:hidden;
				background: transparent;
				color: transparent;
    }
}
@-webkit-keyframes cssAnimation {
    to {
        width:0;
        height:0;
        visibility:hidden;
				background: transparent;
				color: transparent;
    }
}