I wanted to add something here for reference. I found that one of my SVG files doesn’t need the height and width to be set. But the other one does.
The SVG which works fine without the setting looks like this:
(note how it specifies width=“16px” height=“16px” in its code)
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="16px" height="16px" viewBox="0 0 16 16" version="1.1">
<!-- Generator: Sketch 46.2 (44496) - http://www.bohemiancoding.com/sketch -->
<title>Social Icons/facebook-icon-white</title>
<desc>Created with Sketch.</desc>
<defs/>
<g id="Assets" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd">
<g id="Social-Icons/facebook-icon-white" fill="#FFFFFF">
<path d="M5.6676666,16 L5.6676666,8.68304873 L3,8.68304873 L3,5.88421491 L5.66830941,5.88421491 L5.66830941,3.77176177 C5.66830941,1.3394419 7.25605314,5.68434189e-14 9.60552818,5.68434189e-14 C10.7304478,5.68434189e-14 11.7178059,0.0733027905 12,0.106622241 L12,2.68554769 L10.3286908,2.68554769 C9.05078209,2.68554769 8.81165631,3.24531445 8.81165631,4.07163682 L8.81165631,5.88421491 L11.8695093,5.88421491 L11.472252,8.68304873 L8.81165631,8.68304873 L8.81165631,16 L5.66188129,16 L5.6676666,16 Z" id="Icon"/>
</g>
</g>
</svg>
And the one which doesn’t work without the setting looks like this:
<!-- Generator: Adobe Illustrator 23.0.4, SVG Export Plug-In . SVG Version: 6.00 Build 0) -->
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.2" baseProfile="tiny" id="Layer_1" x="0px" y="0px" viewBox="0 0 16 16" xml:space="preserve">
<title>Social Icons/facebook-icon-white</title>
<desc>Created with Sketch.</desc>
<path fill="#FFFFFF" d="M3.6,2.4C3.6,3.3,2.9,4,2.1,4S0.5,3.2,0.5,2.4c0-0.9,0.7-1.6,1.5-1.6S3.6,1.5,3.6,2.4z M3.6,5.2H0.5v10h3.1 V5.2z M8.6,5.2H5.5v10h3.1V9.9c0-2.9,3.8-3.2,3.8,0v5.2h3.1V8.9c0-4.9-5.6-4.7-6.9-2.3C8.6,6.5,8.6,5.2,8.6,5.2z"/>
</svg>