# Equation no not showing in align environment

I am preparing a document that has only one equation. I tried to write it using both the align and equation environment. But surprisingly, none worked for me. When I used the align environment, no equation no was shown. When I used the equation environment, the equation no was 0 (zero).

No equation no is shown with the align environment

Equation no is set to zero with equation environment

I have tried writing only the equation with all used packages in a separate tex file and that worked as expected. So, I couldn't generate a minimal example. As my whole code is too large to share here, I am sharing an overleaf link of the code.The link is: https://www.overleaf.com/read/gsnqfcjdhrfn

The equation is between 117 and 120 lines (at the bottom of the code). How can this problem be solved?

Edit: As I didn't know exactly what was causing the problem, I couldn't add any code here. But as @campa said in a comment, without a code this question will be pointless in the future. Also, @daleif pointed out the problem in the code. So, I am adding a minimal working example here.

\documentclass[12pt]{report}

\usepackage{graphicx}
\usepackage{xcolor}
\usepackage{ragged2e}
\usepackage{tabularx}
\usepackage{multicol}
\usepackage{amsmath}

\begin{document}
\begin{titlepage}
blah blah blah
\end{titlepage}
\nonumber
blah blah blah

The swing equation of a power system is:
\begin{align}
2\times H \times f \times \frac{df}{dt} = P_m - P_e
\label{eqn1}
\end{align}
where $f$ is the system frequency, $H$ is the inertia constant,
$t$ denotes time, $P_m$ is the input mechanical power and $P_e$
is the output electrical power.
\end{document}

• Please post the relevant part of the code here. Links to external pages are pointless as the question will become useless when the link disappears. Nov 14, 2020 at 19:04
• @campa I am not understanding why it's happening and thus can't exactly say which part is relevant. That's why I haven't added the code here. Nov 14, 2020 at 19:09
• What is that nonumber doing right after the title page? Additionally you're making a lit of mistakes in that code. Nov 14, 2020 at 19:12
• Since you're not providing code here (always preferred as links rot over time) your question might not be useful to others. But please look up a good intro to larex as you're making a lot of mistakes in that code. Nov 14, 2020 at 19:18
• Thanks for your kind suggestion. I will provide a mwe to make it bit more useful. Nov 14, 2020 at 19:21

There is no alignment here so you should use equation not align but the reason that you have no number is that you have used
   \nonumber

• Possibly \nonumber might check for not being in a display… Nov 14, 2020 at 21:10