It sounds as though you're not in a modern document mode. Internet Explorer 11 shows the SVG just fine when you're in Standards Mode. Make sure that if you have an x-ua-compatible
meta tag, you have it set to Edge, rather than an earlier mode.
<meta http-equiv="X-UA-Compatible" content="IE=edge">
You can determine your document mode by opening up your F12 Developer Tools and checking either the document mode dropdown (seen at top-right, currently "Edge") or the emulation tab:
If you do not have an x-ua-compatible
meta tag (or header), be sure to use a doctype that will put the document into Standards mode, such as <!DOCTYPE html>
.