If this happens try to set useCorsProxy to false in your feed config. Like this:
	modules: [
		{
			module: "newsfeed",
			position: "top_right",
			config: {
				feeds: [
					{
						title: "tagesschau.de",
						url: "https://www.tagesschau.de/xml/rss2/",
						useCorsProxy: false
					}
				]
			}
		},
		{
			module: "MMM-News-QR",
			position: "top_right",
			config: {
				updateType: "push",
				interval: 2000,
				animationSpeed: 2500,
				colorDark: "#fff",
				colorLight: "#000",
				imageSize: 150
			}
		}
	]