HTML Emailer border issue

I have created a HTML email and seem to be having issues on some outlooks and mobile outlook with the table cells borders I have attached an image of the issue there seems to be a thin lines where the table cells are.

CSS

    html { width: 100%; }
    body { -webkit-text-size-adjust: none; -ms-text-size-adjust: none; margin: 0; padding: 0; }
    table { border-spacing: 0; border-collapse: collapse; }
    table td { border-collapse: collapse; font-family: Arial,sans-serif; line-height:1.4 }

HTML

<table  width="600" border="0" cellpadding="0" cellspacing="0" bgcolor="006680" align="center">
            <tr>
                <td height="10" bgcolor="fd6b0d"></td>
            </tr>
        </table>


        <table  width="600" border="0" cellpadding="0" cellspacing="0" bgcolor="006680" align="center">
            <tr>
                <td width="50" bgcolor="fd6b0d"></td>
                <td bgcolor="fd6b0d">
                    <p style="font-family: Verdana; font-size: 28px; color: #fff; margin: 0; padding: 0; line-height: 60px; text-align: center; font-weight: bold;">
                        How Confident Are You?
                    </p>

                </td>
                <td width="50" bgcolor="fd6b0d"></td>
            </tr>
        </table>