Problem using mathpazo fonts

Question

The capital Greek letters, e.g., $\Lambda$, $\Gamma$, $\Omega$ are replaced by black square if I am changing the font style from 'mlmordern' to 'mathpazo'. Please help me with this. I am new here, and do not know, how to post tex environment.

Thanks in advance.

\documentclass[12pt, a4paper, twoside]{report}
\usepackage[utf8]{inputenc}
\usepackage{amsmath, amsthm, amssymb, amsfonts}
\usepackage{times}
\usepackage{pgfplots}
%\usepackage{mathptmx}
%\usepackage[margin=0.9in]{geometry}
\usepackage{mathrsfs}
%\usepackage{subfig}
\usepackage{setspace}
\usepackage{scalerel}
\usepackage{amssymb}
\usepackage{mathpazo}
\usepackage[mathscr]{euscript}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{xcolor}
\newcommand\blfootnote[1]{%
  \begingroup
  \renewcommand\thefootnote{}\footnote{#1}%
  \addtocounter{footnote}{-1}%
  \endgroup
  }
\usepackage[left=3.8cm,right=2.5cm,top=2.5cm,bottom=2.5cm]{geometry}
\usepackage[refpage]{nomencl}
\renewcommand{\nomname}{List of Symbols}
\renewcommand{\pagedeclaration}[1]{\dotfill\hyperpage{#1}}
\makenomenclature
\newcommand{\nm}[2]{\nomenclature{#1}{#2}}
\usepackage{appendix}
\usepackage{color}
\usepackage{fancybox}
\usepackage{lipsum}
\usepackage[bookmarks = true]{hyperref}
\usepackage{caption}
\usepackage{subcaption}
\usepackage{fancyhdr}
\usepackage{breqn}
\usepackage{lineno}
\usepackage{titletoc}
\usepackage[symbol]{footmisc}
\usepackage{flexisym}
\usepackage{relsize}
\DeclareMathAlphabet{\mathscrbf}{OMS}{mdugm}{b}{n}

Test document

\documentclass[12pt, a4paper, twoside]{report}

\usepackage{mathpazo}

\usepackage{breqn}


\begin{document}

lambda $ \Lambda$
\end{document}

Answer 1

mathpazo is rather old, a newer currently maintained Palatino clone math package is newpxmath which appears more compatible with the (still experimental) breqn package.

\documentclass[12pt, a4paper, twoside]{report}


\usepackage{newpxmath}

\usepackage{breqn}



\begin{document}

lambda $ \Lambda$
\end{document}