printbibliography doesn't add the sources

Question

I am writing my thesis and have collected the sources in the thesis.bib file.

This is what is in it:

  title = {Din EN 61131-1 Speicherprogrammierbare Steuerungen - Teil 1: Allgemeine Informationen(IEC 61131-1:2003); Deutsche Fassung EN 61131-1:2003},
  author = {Arbeitsgremium DKE/K 962 - SPS},
  isbn={432},
  series={324},
  year = {2004},
  %doi = {10.31030/9537680},
  publisher = {Beuth Verlag GmbH},
  url = {https://dx.doi.org/10.31030/9537680},
}
@online{IECSiemens,
title = {Normerfüllung nach IEC 61131-3},
url = {https://cache.industry.siemens.com/dl/files/932/8790932/att_82256/v1/norm_tab.pdf },
urldate = {29-06-21},
}
@online{IECLothar,
title = {DIE NORM IEC 61131},
url = {https://lothar-michaelis.de/html/teil_1/iec61131.html},
urldate = {29-06-21},
}
@book{TheisWPF,
  title = {Einstieg in WPF 4.5: Grundlagen und Praxis},
  author = {Thomas Theis},
  isbn={3836219670},
  series={2},
  year = {2012},
  pages = {15--17},
  publisher = {Galileo Computing},
}
@online{MicroCSh,
title = {Überblick über C# },
author = {Bill Wagner},
date   = {28-01-21},
url = {https://docs.microsoft.com/de-de/dotnet/csharp/tour-of-csharp/},
urldate = {29-06-21},
}
@online{objectiF,
title = {objectiF. Die Software für modellgetriebene Entwicklung und Transformation.},
url = {https://www.microtool.de/produkte/objectif/},
urldate = {29-06-21},
}
@online{VisualStudio,
title = {Visual Studio},
date   = {25-06-21},
url = {https://de.wikipedia.org/wiki/Visual_Studio},
urldate = {29-06-21},
}
@online{Blend,
title = {Microsoft Blend},
date   = {04-06-21},
url = {https://de.wikipedia.org/wiki/Microsoft_Blend},
urldate = {29-06-21},
}
@online{SauSch,
title = {Stadler + Schaaf Hauptseite},
url = {https://www.stadler-schaaf.de/},
urldate = {29-06-21},
}
@online{SauSchIT,
title = {Stadler + Schaaf Industrial IT},
url = {https://www.stadler-schaaf.de/kompetenz/industrial-it/},
urldate = {29-06-21},
}
@online{SauSchITF,
title = {Stadler + Schaaf Industrial IT Flyer},
url = {https://www.stadler-schaaf.de/wp-content/uploads/2018/10/stadler_schaaf_flyer_industrial_it-1.pdf },
urldate = {29-06-21},
}

But when I call \printbibliography it does nothing.

The full document with \printbibliography:

\documentclass[oneside, ngerman,final,12pt]{sdqthesis}
\author{Etalia}
\title{The Title}
\thesistype{Etalias Thesis}
\reviewerone{Prof. Dr. one}
\reviewertwo{Prof. Dr. two}
\advisorone{guy}
\editingtime{11. March 3021}{30. January 3022}
\settitle
\hyphenation{
}
\usepackage[citestyle=numeric,style=numeric,backend=biber]{biblatex}
\usepackage{subfig}
\usepackage{pdflscape}
\addbibresource{thesis.bib}   %here the file loaded into the thesis or at least I believe that it is
\begin{document}
\setpdf
\maketitle
\frontmatter
\input{sections/declaration.tex}
\mainmatter
\setcounter{page}{3}
\begin{otherlanguage}{English}
\includeabstract
\end{otherlanguage}
\tableofcontents
\listoffigures
%\listoftables I removed that one as I do not need it, I don't think it is interfeering with the printbibliography is it?
\input{sections/introduction.tex}
\input{sections/content Grundlagen.tex}
\input{sections/content Planung und Definierung.tex}
\input{sections/content Design.tex}
\input{sections/content Erstellung des UI.tex}
\input{sections/evaluation.tex}
\input{sections/conclusion.tex}
%% --------------------
%% |   Bibliography   |
%% --------------------
%% Add entry to the table of contents for the bibliography
\printbibliography[heading=bibintoc, title={Quellen}] %This seems to do nothing and that is my problem
%% ----------------
%% |   Appendix   |
%% ----------------
%\appendix
%\input{sections/appendix.tex} %I removed that one as well.
\end{document}

Now I have all the citations spread over my document and use them with This is just the normal text. \cite{objectiF}. Usually at the end of a paragraph.

When I create the PDF I use the Option pdfLaTeX+MakeIndex+BibTex. I tried it two ways. The first way was to simply press "start", and I also tried to start the bib file separately first an then the main TeX file. (The one you see here.)

Both times it just runs throug without error but no Sources anywhere.

I've got those warnings when I run main document that seem to have something to do with bib:

Package biblatex Warning: No localisation for language 'english' loaded. Please rerun LaTeX to ensure languages can be requested properly.

I do not know where it wants a localisation though.

introduction.tex 23 LaTeX Warning: Citation 'SauSch' on page 8 undefined on input line 23.

These are everywhere, where I try to cite.

thesis.tex LaTeX Warning: There were undefined references.

thesis.tex LaTeX Warning: Label(s) may have changed. Rerun to get cross-references right.

thesis.tex Package rerunfilecheck Warning: File thesis.out' has changed. Rerun to get outlines right or use package bookmark'.

thesis.tex Package biblatex Warning: Please (re)run Biber on the file: thesis and rerun LaTeX afterwards.

and that one

thesis.tex Package biblatex Warning: Please (re)run Biber on the file: thesis and rerun LaTeX afterwards.

So if someone sees what I did wrong and can help, would be much appreciated. Further questions:

• Do I need to start bib on it's own before running the main TeX file?
• How sensitive is the .bib file?
• Is it necessary to have all parameters to a citation object? For example can I run a @book with only the title filled? Or need they every parameter in the right order and filled? And if one of them is not running because I made such an error, would that instantly take out the whole .bib or can the rest still work if one of them has a bad format?

Oh and before I forget, I am running this with MiKTeX on Windows.

Edit: the sdqthesis.cls:

\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{sdqthesis}[2020-06-26 v1.3.5 Student thesis class]
% Language options. German is also needed in English thesis for the abstract
\DeclareOption{ngerman}{\PassOptionsToPackage{\CurrentOption}{babel}}
\DeclareOption{english}{\PassOptionsToPackage{main=\CurrentOption,ngerman}{babel}}
\DeclareOption*{\PassOptionsToClass{\CurrentOption}{scrbook}}
\ProcessOptions\relax
% Used to detect language families
\RequirePackage{translations}
%% ---------------------------------------------------------------
%% | Based on KOMAscript by Markus Kohm http://www.komascript.de |
%% ---------------------------------------------------------------
\LoadClass{scrbook}
%% --------------
%% | Typography |
%% --------------
% T1 font encoding
\RequirePackage[T1]{fontenc}
\RequirePackage[utf8]{inputenc}
% serif type: Linux Libertine
\RequirePackage{libertine}
% Linux Libertine in math mode
\RequirePackage[libertine]{newtxmath}
% grotesque type: Adobe Source Sans Pro
\RequirePackage[scaled=.92]{sourcesanspro}
% monospace type: Bera Mono
\RequirePackage[scaled=.78]{beramono}
% semi-bold type (for subsections and paragraphs)
\newcommand*{\sbdefault}{sb}
\DeclareRobustCommand{\sbseries}{%
  \not@math@alphabet\sbseries\relax
  \fontseries\sbdefault\selectfont}
\DeclareTextFontCommand{\textsb}{\sbseries}
\addtokomafont{subsection}{\sbseries}
\addtokomafont{subsubsection}{\sbseries}
\addtokomafont{paragraph}{\sbseries}
% microtype for nicer typography
\RequirePackage[protrusion=true,expansion=true]{microtype}
% commands for code and model keywords in text
\newcommand{\code}[1]{\texttt{\hyphenchar\font45\relax #1}}
\newcommand{\model}[1]{\textsf{#1}}
% nicer spacing for enumerations
\RequirePackage{enumitem}
%% ---------------
%% | Page Layout |
%% ---------------
\KOMAoptions{
   fontsize=12pt,
   paper=a4,
   titlepage=true,
   headinclude=true,
   footinclude=false,
}
% Margins
\if@twoside%
  \typearea[20mm]{15} % twoside
\else% 
  \typearea[10mm]{15} % oneside
\fi%
\RequirePackage[headsepline,draft=false]{scrlayer-scrpage}
\pagestyle{scrheadings}
\clubpenalty=10000 %prevent orphans
\widowpenalty=10000 %prevent widows
%% --------------
%% | Title page |
%% --------------
% Logos
\newcommand{\thegrouplogo}{S+Slogo}
\newcommand{\grouplogo}[1]{\renewcommand{\thegrouplogo}{#1}}
\newcommand{\printgrouplogo}{\includegraphics[height=2.6cm]{logos/\thegrouplogo}}
\newcommand{\nogrouplogo}{\renewcommand{\printgrouplogo}{}}
\titlehead{%
% HS
{\includegraphics[height=1.8cm]{logos/hs_os}}
\hfill
% SDQ logo
\printgrouplogo
\ThisCenterWallPaper{1}{title-background.pdf}
}
%
\setkomafont{title}{\huge\sffamily\bfseries}
\setkomafont{subtitle}{\normalfont\large}
\uppertitleback{Hochschule Karlsruhe - Technik und Wirtschaft\ Fakultät für Informatik und Wirtschatsinformatik\ Postfach 2440\ 76012 Karlsruhe}
%% variables for title page
\newcommand{\theinstitute}{\ifcurrentbaselanguage{English}
    {Institute for Program Structures and Data Organization (IPD)}
    {bei Stadler+Schaaf Mess- und Regeltechnik GmbH}}
\newcommand{\thethesistype}{}
\newcommand{\thereviewerone}{}
\newcommand{\thereviewertwo}{}
\newcommand{\theadvisorone}{}
\newcommand{\theadvisortwo}{}
\newcommand{\theeditstart}{}
\newcommand{\theeditend}{}
%% formatting commands for titlepage
\newcommand{\thesistype}[1]{\subtitle{\vskip2em #1 \ifcurrentbaselanguage{English}{of}{von}}%
\renewcommand{\thethesistype}{#1}}
\newcommand{\myinstitute}[1]{\renewcommand{\theinstitute}{#1}}
\newcommand{\reviewerone}[1]{\renewcommand{\thereviewerone}{#1}}
\newcommand{\reviewertwo}[1]{\renewcommand{\thereviewertwo}{#1}}
\newcommand{\advisorone}[1]{\renewcommand{\theadvisorone}{#1}}
\newcommand{\advisortwo}[1]{\renewcommand{\theadvisortwo}{#1}}
\newcommand{\editingtime}[2]{%
\renewcommand{\theeditstart}{#1}%
\renewcommand{\theeditend}{#2}%
%% do not show the date
\date{}
}
\newcommand{\settitle}{%
\publishers{%
\large
\ifcurrentbaselanguage{English}{at the Department of Informatics}%
{an der Fakultät für Informatik und Wirtschaftsinformatik}\
\theinstitute\[2em]
\begin{tabular}{l l}
  \ifcurrentbaselanguage{English}{Reviewer}{Erstgutachter}: & \thereviewerone\
  \ifcurrentbaselanguage{English}{Second reviewer}{Zweitgutachter}: & \thereviewertwo\
  \ifcurrentbaselanguage{English}{Advisor}{Betreuender Mitarbeiter}: &  \theadvisorone\
  % if there is no second advisor, do not output this line
  \ifthenelse{\equal{\theadvisortwo}{}}{}{%
  \ifcurrentbaselanguage{English}{Second advisor}{Zweiter betreuender Mitarbeiter}: & \theadvisortwo\
  }
\end{tabular}
\vskip2em
\theeditstart{} -- \theeditend
}
}
%% -----------------------------
%% | Abstract/Acknowledgements |
%% -----------------------------
\newcommand{\abstract}[1][\abstractname]{\chapter{#1}}
\newcommand{\Abstract}[1][\abstractname]{\chapter{#1}\addcontentsline{toc}{chapter}{#1}}
\def\ackname{Acknowledgments}
\def\abstractname{Abstract}
\def\switcht@deutsch{\svlanginfo
    \def\ackname{Danksagung}
    \def\abstractname{Kurzfassung}
}
\def\switcht@english{\svlanginfo
    \def\ackname{Acknowledgements}
    \def\abstractname{Abstract}
}
%% In English theses, an additional German Abstract is needed.
\newcommand{\includeabstract}{
\ifcurrentbaselanguage{English}{
% include English and German abstracts
\def\abstractname{Abstract}
\input{sections/abstract_en.tex}
\begin{otherlanguage}{ngerman}
\input{sections/abstract_de.tex}
\end{otherlanguage}
}{
% include only German abstract
\include{sections/abstract_de}
}
}
%% ------------
%% | Packages |
%% ------------
% draft mode
\RequirePackage{ifdraft}
\RequirePackage{ifthen}
% enumerate subsubsections
\setcounter{secnumdepth}{3}
% wallpaper for title page (KIT-Frame)
\RequirePackage{wallpaper}
% subimport of files
\RequirePackage{import}
% languages
\RequirePackage{babel}
\RequirePackage{csquotes}
% hyphenation for compound words
\RequirePackage[shortcuts]{extdash}
% nice tables
\RequirePackage{booktabs}
\RequirePackage{longtable}
\RequirePackage{array}
% show graphics in draft mode
\RequirePackage{graphicx}
\setkeys{Gin}{draft=false}
\usepackage{wrapfig}
% appendix
\RequirePackage[toc,title,header]{appendix}
\noappendicestocpagenum
% PDF specific packages
\RequirePackage[hyphens]{url}
\RequirePackage[breaklinks,colorlinks=false]{hyperref}
\newcommand\setpdf{
    \hypersetup{%
    pdftitle={\thethesistype},%
    pdfsubject={@title},%
    pdfauthor={@author},%
    pdfborder={0 0 0},%
    }%
    \let\theauthor@author
}