Issues with ad insertions in AWS MediaTailor

Hello,

I configured ad insertions in AWS MediaTailor by providing source content without ad markers and an XML file with VMAP to the ADS URL. When watching the playback URL, the video specified in VMAP was not being inserted into the source content. I checked the logs in CloudWatch, and they showed the following:

"skippedAds": [
    {
        "creativeUniqueId": "00001",
        "adMezzanineUrl": "https://d3re4i3vgppvr8.cloudfront.net/Media/Bumpers/AD-caribbean-15-HD.mp4",
        "skippedReason": "TRANSCODE_ERROR",
        "vastDuration": 15
    }
]

What could be the reason for this?

I am attaching the VMAP file I created below.

VMAP XML file

<vmap:VMAP xmlns:vmap="http://www.iab.net/videosuite/vmap" version="1.0">
    <vmap:AdBreak timeOffset="start" breakType="linear" breakId="preroll">
        <vmap:AdSource id="preroll-ad-1" allowMultipleAds="false" followRedirects="true">
            <vmap:AdTagURI templateType="vast3">
                <![CDATA[ https://n8ljfs0h09.execute-api.us-west-2.amazonaws.com/v1/ads?duration=15 ]]>
            </vmap:AdTagURI>
        </vmap:AdSource>
    </vmap:AdBreak>
</vmap:VMAP>

https://n8ljfs0h09.execute-api.us-west-2.amazonaws.com/v1/ads?duration=15

<VAST xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="3.0">
    <Ad sequence="1">
        <InLine>
            <AdSystem>2.0</AdSystem>
            <AdTitle>AD-caribbean2-15</AdTitle>
            <Impression>
                <![CDATA[ https://n8ljfs0h09.execute-api.us-west-2.amazonaws.com/v1/impression ]]>
            </Impression>
            <Creatives>
                <Creative sequence="1" apiFramework="inLine" id="00002">
                    <Linear>
                        <Duration>00:00:15</Duration>
                        <MediaFiles>
                            <MediaFile id="00002" delivery="progressive" type="video/mp4" width="1280" height="720">
                                <![CDATA[ https://d3re4i3vgppvr8.cloudfront.net/Media/Bumpers/AD-caribbean2-15-HD.mp4 ]]>
                            </MediaFile>
                        </MediaFiles>
                    </Linear>
                </Creative>
            </Creatives>
        </InLine>
    </Ad>
</VAST>