post template

Hello, I have a problem with the post template. If I insert the following code there, it will not be output correctly. Actually the text should be in the foreground and a picture as background in the post appears the text as given but the background picture is not shown. Tried the Post Tempel Code with another Autopost, it works there. Do you have an idea what that could be?

<!-- wp:blockspare/content-box {"imgURL":"https://bloggernews.de/wp-content/uploads/2020/05/youtuber-2838945_1280.jpg","imgID":702} -->
<div class="aligncenter blockspare-content-wrapper blockspare-blocks aligncenter has-background style-1" style="text-align:center;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:30px;margin-bottom:30px"><div class="content-img-wrap"><img src="https://bloggernews.de/wp-content/uploads/2020/05/youtuber-2838945_1280.jpg" alt="" class=""/></div><div class="blockspare-section-wrapper" style="box-shadow:;background-color:#fff"><div class="blockspare-section-header-wrapper" style="border-color:#8b249c"><div class="blockspare-section-head-wrap blockspare-style1 blockspare-center"><div class="blockspare-title-subtitle-wrap"><div class="blockspare-section-header-wrapper blockspare-blocks aligncenter" style="text-align:center;padding-top:0px;padding-right:0px;padding-bottom:0px;margin-top:0px;margin-bottom:0px;padding-left:0px;background-color:transparent"><div class="blockspare-section-head-wrap blockspare-style1 blockspare-center"><div class="blockspare-title-wrapper"><span class="blockspare-title-dash blockspare-upper-dash" style="border-color:#8b249c"></span><h2 class="blockspare-title" style="color:#404040;font-size:32px;padding-top:5px;padding-bottom:5px">Enter Title</h2><span class="blockspare-title-dash blockspare-lower-dash" style="border-color:#8b249c"></span></div><div class="blockspare-subtitle-wrapper"><span class="blockspare-title-dash blockspare-upper-dash" style="border-color:#8b249c"></span><p class="blockspare-subtitle" style="font-size:18px;color:#6d6d6d;padding-top:5px;padding-bottom:5px">{itemcontent}</p><span class="blockspare-title-dash blockspare-lower-dash" style="border-color:#8b249c"></span></div></div></div></div></div><div class="blockspare-desc-btn-wrap"><p style="color:#6d6d6d">Add your description here...</p></div></div></div></div>
<!-- /wp:blockspare/content-box -->