Cite in LaTeX is not working in TexStudio - pdf

Question

i have the issue that when i want to quote anything in LaTeX the PDF shows only the Name of the Source. in this Case it is Berk.2019
My Document (which i maded shorter as an example):
\documentclass[12pt,a4paper]{article}
\usepackage{amsmath,amssymb}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
\usepackage[backend=biber, style=ieee]{biblatex}
\addbibresource{literatur.bib}
\title{Musterdokument}
\author{Manfred Muster}
\date{\today}
\begin{document}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. \cite{Berk.2019}
\newpage
\printbibliography
\end{document}
And the .bib file:
% This file was created with Citavi 6.14.0.0
#book{Berk.2019,
abstract = {Intro -- Preface -- Contents -- 1 Getting Started -- 1.1 Some Introductory Caveats -- 1.2 What Criminal Justice Risk Assessment Is and Is Not -- 1.3 Difficulties Defining Machine Learning -- 1.4 Setting the Stage -- 1.4.1 A Brief Motivating Example -- 2 Some Important Background Material -- 2.1 Policy Considerations -- 2.1.1 Criminal Justice Risk Assessment Goals -- 2.1.2 Decisions to Be Informed by the Forecasts -- 2.1.3 Outcomes to Be Forecasted -- 2.1.4 Real World Constraints -- 2.1.5 Stakeholders -- 2.2 Data Considerations -- 2.2.1 Stability Over Time -- 2.2.2 Training Data, Evaluation Data, and Test Data -- 2.2.3 Representative Data -- 2.2.4 Large Samples -- 2.2.5 Data Continuity -- 2.2.6 Missing Data -- 2.3 Statistical Considerations -- 2.3.1 Actuarial Methods -- 2.3.2 Building in the Relative Costs of Forecasting Errors -- 2.3.3 Effective Forecasting Algorithms -- 3 A Conceptual Introduction to Classification and Forecasting -- 3.1 Populations and Samples -- 3.2 Classification and Forecasting Using Decision Boundaries -- 3.3 Classification by Data Partitions -- 3.4 Forecasting by Data Partitions -- 3.5 Finding Good Data Partitions -- 3.6 Enter Asymmetric Costs -- 3.7 Recursive Partitioning Classification Trees -- 3.7.1 How Many Terminal Nodes? -- 3.7.2 Classification Tree Instability and Adaptive Fitting -- 4 A More Formal Treatment of Classification and Forecasting -- 4.1 Introduction -- 4.2 What Is Being Estimated? -- 4.3 Data Generation Formulations -- 4.4 Notation -- 4.5 From Probabilities to Classification -- 4.6 Computing (G|X) in the Real World -- 4.6.1 Estimation Bias -- 4.6.2 The Traditional Bias-Variance Tradeoff with Extensions -- 4.6.3 Addressing Uncertainty -- 4.7 A Bit More on the Joint Probability Model -- 4.8 Putting It All Together -- 5 Tree-Based Forecasting Methods -- 5.1 Introduction.},
author = {Berk, Richard},
year = {2019},
title = {Machine Learning Risk Assessments in Criminal Justice Settings},
url = {https://ebookcentral.proquest.com/lib/kxp/detail.action?docID=5615389},
address = {Cham},
publisher = {Springer},
isbn = {978-3-030-02272-3}
}
Do you know what is wrong?
I compile it with TeXStudio and Biber. Let me know if you need any further information