Why am I not able to burst Excel output type when PDF bursts fine using the same bursting control fi

Why am I not able to burst Excel output type when PDF bursts fine using the same bursting control file?

<?xml version="1.0" encoding="UTF-8"?>
<xapi:requestset xmlns:xapi="http://xmlns.oracle.com/oxp/xapi" type="bursting">
<xapi:request select="/XXCM_WON_BID/LIST_G_EMAIL_ADDRESS/G_EMAIL_ADDRESS">
<xapi:delivery>
<xapi:email server="ip" port="ip" from="sysadmin" reply-to="sysadmin">
<xapi:message id="123" to="${EMAIL_ADDRESS}" attachment="true" content-type="html/text" subject="Won Bid Report">
Hi Sir/Madam,
   Please find  Won Bid Report in the attachment.

Regards,
CoinMach.

Please don't reply to this mail.

</xapi:message>
</xapi:email>
</xapi:delivery>