Hello! author name, email etc are not showing. Thanks for any help

documentclass[a4paper,titlepage,oneside, reqno]{amsart}
usepackage[left=2.7cm, right=2.5cm, top=3cm]{geometry}
usepackage[utf8]{inputenc}
usepackage[T2A, T1]{fontenc}
usepackage[numbers]{natbib}
usepackage[dutch,polish,swedish,french,german,russian,main=english]{babel}
letpllllll
letlllrelax
usepackage{lmodern}
usepackage[tipa,combine]{ucs}
usepackage[colorlinks]{hyperref}
hypersetup{colorlinks,linkcolor={green!55!black},citecolor={green!55!black},urlcolor={green!55!black}} usepackage{url}
usepackage[pdftex]{graphicx}
usepackage{amsthm,amssymb,bm}
usepackage{thmtools}
usepackage{environ}
usepackage{nicefrac}  
usepackage[dvipsnames]{xcolor}
usepackage{tikz}
usepackage[affil-it]{authblk}
usepackage{epstopdf}
usepackage{amsfonts,amssymb,amsbsy}
usepackage{mathtools}
usepackage{amsmath}
usepackage{nccmath}
usepackage{tabu}
usepackage{tabularx}
usepackage{multirow}
usepackage{bbm}
usepackage{comment}
usepackage{microtype} 
usepackage{placeins}
makeatletter
letmytagform@=tagform@
deftagform@#1{maketag@@@{color{green!55!black}(#1)}}
makeatother
newcommand{eqnumcolor}{color{green!55!black}}
newtheorem{theorem}{Theorem}[section]
newtheorem{lemma}[theorem]{Lemma}
newtheorem{proposition}[theorem]{Proposition}
newtheorem{corollary}[theorem]{Corollary}
newtheorem{observation}[theorem]{Observation}
newtheorem{definition}[theorem]{Definition}
newtheorem{remark}[theorem]{Remark}
newtheorem{example}[theorem]{Example}
newtheorem{assumption}[theorem]{Assumption}
newtheorem{problem}[theorem]{Problem}
parindent0mm
usepackage{helvet}
usepackage{titlesec}
usepackage{parskip}

titleformat{chapter}
  {normalfontfontsize{12}{15}sffamilybfseries}
  {thechapter}
  {0.5em}
  {}

titleformat{section}
  {normalfontfontsize{10}{15}sffamilybfseries}
  {thesection}
  {0.5em}
  {}

titleformat{subsection}
  {normalfontfontsize{8}{13}sffamilybfseriesslshape}
  {thesubsection}
  {0.5em}
  {}
  
title[xyz]{xyz}

author{}
email{}


begin{document}
maketitle

Hello! author name, email etc are not showing. Thanks for any help.