create long table within multiple pages

Question

need to create long table within multiple pages.My code gives 3 errors "Error: Package array Error: Illegal pream-token (\renewcommand): `c' used." and "Error: Misplaced \noalign. " and "Error: Misplaced \omit.'" my code is,

 \documentclass[12pt,a4paper,oneside]{report}
\usepackage{placeins}
\usepackage{longtable}
\usepackage[fleqn]{amsmath}
\usepackage{booktabs}
\usepackage{tabularx}
\begin{document}


 \FloatBarrier
 \begin{longtable}[!ht]
 \renewcommand{\arraystretch}{1}
 \caption[Test Cases for Login Subsystem]{Test Cases for Login Subsystem}
 \label{Test Cases for Login Subsystem}\centering
 \begin{tabularx}{\textwidth}{|X|X|X|X|}
 \toprule
 \bfseries Test Objective/Scenario & \bfseries Function & \bfseries Input & \bfseries Expected Outcome\\ \midrule
 Login   & Login function  & Insert dfdgfd ffgfgfgdfg \& dfgdfgdf fdgfg gf gfgfg fdgdfgdfgdfgf \\ \midrule
 ...........................
  vvv &  vvv & Insert correct user name \& gdfgfdg gfgfdgfgfgdfgdf fgfgfgd dfgfdgfg  \\\bottomrule
 \end{tabularx}
 \end{longtable}
 \FloatBarrier


 \FloatBarrier
 \begin{longtable}[!ht]
 \renewcommand{\arraystretch}{1}
 \caption[Test Cases for Admin Subsystem]{Test Cases for Admin Subsystem}
 \label{Test Cases for Admin Subsystem}\centering
 \begin{tabularx}{\textwidth}{|X|X|X|X|}
 \toprule
  \bfseries Test Objective/Scenario & \bfseries Function & \bfseries Input & \bfseries Expected Outcome\\ \midrule
  Create users  & Create a new user & Fill the text fields in user interface & Adding the user to database  \\ \midrule
  .....................
  Manage info.from re-insurance \& legal dept.  & Edit dept.info., functions  & Edit the text fields  & Editing the database \\\bottomrule
 \end{tabularx}
 \end{longtable}
 \FloatBarrier

\end{document}     

Answer 1

longtable and tabularx cannot be mixed this way. You should use either tabularx or longtable inside a Table enivironment.

Hoever, if you want to mix both properties try tabu package or older packages like ltablex.