Nu HTML Checker show "Possible misuse of aria-label." for the special structure

I designed some special structure for the project effect and set the aria-label attribute on the tag. But Nu HTML Checker tells me that "Possible misuse of aria-label. "

<h3 aria-label="Contact">
    <span aria-hidden="true" class="char-wrapper">c
        <svg class="char-svg char--c">
            <use xlink:href="#char--c"></use>
        </svg>
    </span>
    <span aria-hidden="true" class="char-wrapper">o
        <svg class="char-svg char--o">
            <use xlink:href="#char--o"></use>
        </svg>
    </span>
    <span aria-hidden="true" class="char-wrapper">n
        <svg class="char-svg char--n">
            <use xlink:href="#char--n"></use>
        </svg>
    </span>
    <span aria-hidden="true" class="char-wrapper">t
        <svg class="char-svg char--t">
            <use xlink:href="#char--t"></use>
        </svg>
    </span>
    <span aria-hidden="true" class="char-wrapper">a
        <svg class="char-svg char--a">
            <use xlink:href="#char--a"></use>
        </svg>
    </span>
    <span aria-hidden="true" class="char-wrapper">c
        <svg class="char-svg char--c">
            <use xlink:href="#char--c"></use>
        </svg>
    </span>
    <span aria-hidden="true" class="char-wrapper">t
        <svg class="char-svg char--t">
            <use xlink:href="#char--t"></use>
        </svg>
    </span>
</h3>

Am I use it wrong? How do I fix this warning?