Companion banner not showing up in Google HTML5 Video Player

I am trying to test a video Ad in Google HTML5 video player. However when I run the ad, the companion banner is not showing up. Here is the companion banner exert from the VAST:

<Creative id="65393060" sequence="1">
 <CompanionAds>
  <Companion id="65393060" width="300" height="250">
   <StaticResource creativeType="image/jpeg"><![CDATA[https://upload.wikimedia.org/wikipedia/commons/2/24/Ad-MediumRectangle-300x250.jpg]]></StaticResource>
   <TrackingEvents>
    <Tracking event="creativeView"><![CDATA[https://googleads4.g.doubleclick.net/pcs/view?xai=AKAOjstsTn-EaW1qCpFP8ZfnnD3WA-FvBRQQqjL6Zsorvcg_b2mBA825XyOmESX3oEFPWEYsBfGOZnwFDoULoM_W2XoJotTnj5_cHibpaP0QuuKj&sig=Cg0ArKJSzHCpDSHDWEEtEAE&urlfix=1&adurl=]]></Tracking>
   </TrackingEvents>
   <CompanionClickThrough><![CDATA[https://adclick.g.doubleclick.net/pcs/click?xai=AKAOjstsTn-EaW1qCpFP8ZfnnD3WA-FvBRQQqjL6Zsorvcg_b2mBA825XyOmESX3oEFPWEYsBfGOZnwFDoULoM_W2XoJotTnj5_cHibpaP0QuuKj&sig=Cg0ArKJSzCLZtsCz6JLn&urlfix=1&adurl=https://www.adobe.com/marketing-cloud/customer-experience.html%3Fsdid%3D162BDWN7%26mv%3Ddisplay]]></CompanionClickThrough>
  </Companion>
 </CompanionAds>
</Creative>

Can anyone tell me why? I was testing this here:

https://developers.google.com/interactive-media-ads/docs/sdks/html5/vastinspector

Solution

Your Companion Ad config looks fine. I'd copied the sampel-vast.xml from google and added your Companion - so it looks like:

<VAST xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="vast.xsd" version="3.0">
    <Ad id="...">
        <InLine>
            <AdSystem>...</AdSystem>
            <AdTitle>...</AdTitle>
            <Description>...</Description>
            <Error>...</Error>
            <Impression>...</Impression>
            <Creatives>
                <Creative id="..." sequence="1">
                    <Linear skipoffset="...">...</Linear>
                </Creative>
                <Creative id="..." sequence="1">
                    <CompanionAds>
                        <Companion id="..." width="300" height="250">
                            <StaticResource creativeType="image/jpeg"><![CDATA[https://upload.wikimedia.org/wikipedia/commons/2/24/Ad-MediumRectangle-300x250.jpg]]></StaticResource>
                            <TrackingEvents>
                                <Tracking event="creativeView"><![CDATA[https://googleads4.g.doubleclick.net/pcs/view?xai=AKAOjstsTn-EaW1qCpFP8ZfnnD3WA-FvBRQQqjL6Zsorvcg_b2mBA825XyOmESX3oEFPWEYsBfGOZnwFDoULoM_W2XoJotTnj5_cHibpaP0QuuKj&sig=Cg0ArKJSzHCpDSHDWEEtEAE&urlfix=1&adurl=]]></Tracking>
                            </TrackingEvents>
                            <CompanionClickThrough><![CDATA[https://adclick.g.doubleclick.net/pcs/click?xai=AKAOjstsTn-EaW1qCpFP8ZfnnD3WA-FvBRQQqjL6Zsorvcg_b2mBA825XyOmESX3oEFPWEYsBfGOZnwFDoULoM_W2XoJotTnj5_cHibpaP0QuuKj&sig=Cg0ArKJSzCLZtsCz6JLn&urlfix=1&adurl=https://www.adobe.com/marketing-cloud/customer-experience.html%3Fsdid%3D162BDWN7%26mv%3Ddisplay]]>    </CompanionClickThrough>
                        </Companion>
                    </CompanionAds>
                </Creative>
            </Creatives>
            <Extensions>...</Extensions>
        </InLine>
    </Ad>
</VAST>

and it works.

Potential issues could be:

Creative \ sequence missmatch (Linear part not provided in question)

Companion \ sequence needs to match Linear \ sequence
CORS resp. Access-Control-Allow-Origin problems

If you see errors in the console of your browser regarding Access-Control-Allow-Origin problems, you might want to edit your server configuration.
A fast solution would be for example to edit .htaccess file in your apache www directory - like:

<IfModule mod_headers.c> Header set Access-Control-Allow-Origin https://imasdk.googleapis.com Header set Access-Control-Allow-Credentials true </IfModule>

If this wasn't helpfull at all, you will need to add some more informations to your question. Like:

browsers console output
full vast.xml
server specifics resp. which option you choosed VAST XML or VAST TAG

Have a nice day.