Thank you for your question and reaching out.
The PowerShell newline indicator is n, and can only be used in double quotes. Single quotes will print the actual "n".
For Example :
$body = "first line" + "`n" + "second line"
Also, One solution would be to use <br /> to break lines and specify the switch -BodyAsHtml so that body would be treated as html and email client would display it correctly, alternatie approach would be to use `n for line breaks and keep body as text.
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