We actually had this problem earlier and resolved it at the time, not sure why it came back. Any video thumbnails fail to load completely, showing just a placeholder instead. The console reports the same error for each thumbnail, an example: qrc:/qt/qml/org/kde/plasmatube/ui/components/VideoListItem.qml:53:9: QML QQuickImage: Error decoding: https://proxy.youtube.fam-ribbers.com/vi/NPqDIwWMtxg/hqdefault.jpg?host=i.ytimg.com&rs=AOn4CLDE4s7_-YKbJqQ2HxLu0lg8ap1hIg&sqp=-oaymwEcCNACELwBSFXyq4qpAw4IARUAAIhCGAFwAcABBg%3D%3D: Unsupported image format That image loads just fine in a browser however.