I can see it in my lyx editor there is number in my section

but when I render the pdf there is no number in my section

anyone can help me? I think there is a problem with my preamble but I don't know which one because when I delete all my preamble the number is shown
It's seems the problem is with \usepackage{titlesec}
what make me confuse is
it only happen in my computer,
when I try to render the same file in my friend's computer the number is shown
my latex preamble
%% \renewcommand{\chapter}[1]{\chapter[#1]{\centering #1}}
\usepackage{titlesec}
\usepackage{graphicx}
\usepackage{pdflscape}
\usepackage{colortbl}
\usepackage{amsmath}
\usepackage{color}
\usepackage{tocbibind}
\usepackage{url}
\usepackage[titletoc]{appendix}
\definecolor{lineno}{rgb}{0.5,0.5,0.5}
\definecolor{bcolor}{rgb}{0.98,0.98,0.98}
\definecolor{code}{rgb}{0,0.1,0.6}
\definecolor{codesty}{rgb}{0.7,0.1,0.1}
\definecolor{commandsty}{rgb}{0.1,0.5,0.0}
\definecolor{keywordsty}{rgb}{0.4,0.0,0.4}
\definecolor{stringsty}{rgb}{1.0,0.5,0.0}
\titleformat{\chapter}[display]
{\normalfont\huge\bfseries\centering}{\chaptertitlename\thechapter}{20pt}{\Huge}
\renewcommand{\contentsname}{Table of Contents}
\setlength{\headheight}{15pt}
\pagestyle{fancy}
\renewcommand{\chaptermark}[1]{\markboth{Chapter \thechapter.\ #1}{}}
\renewcommand{\sectionmark}[1]{\markright{\thesection.\ #1}{}}
\fancyhf{}
\fancyhead[LE,RO]{\thepage}
\fancyhead[RE]{\textit{\nouppercase{\leftmark}}}
\fancyhead[LO]{\textit{\nouppercase{\rightmark}}}
\fancypagestyle{plain}{ %
\fancyhf{} % remove everything
\fancyfoot[C]{\thepage}
\renewcommand{\headrulewidth}{0pt} % remove lines as well
\renewcommand{\footrulewidth}{0pt}}
\usepackage[margin=10pt,font=small,labelfont=bf,labelsep=endash]{caption}
titlesecpackage, unless you need to modify you sections. Which is your document class? Did you try to change it? – Yorgos Sep 29 '16 at 09:50titlesecwith that bug (which explains why it works at your friends computer). Try updating the package -- see http://tex.stackexchange.com/questions/55437/how-do-i-update-my-tex-distribution for instructions on updating. – Torbjørn T. Sep 29 '16 at 11:20