Hi Jüri,
That’s strange. Are you using an image slider or sticky post slider? Also check out if there is featured image available on your post or not if you are using sticky post slider. If you are using an image slider then Could you please send your Site Link? Also Email Us your temporary username and password so that we can help you on this issue. Don’t forget to send your temporary username and password with site link and this forum link too.
Thank You
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