How do i remove this unwanted message displayed in the compiled latex file ("program@epstopdf")?

Question

Here is the relevant code from overleaf:

Rearranging van der Waals' equation for pressure:\\
    \begin{align*}
    \left(&P + \frac{n^2a}{V_i^2}\right)(V_i^2-nb) = nRT\\
    &P+\left(\frac{n^2a}{v^2}\right)=\frac{nRT}{V-nb}\\
    &P = \frac{nRT}{V-nb}-\frac{n^2a}{V^2}\\
    \intertext{Substituting this into the formula for work, integrating from the initial to the final volume:}\\
    W = \int P dV &= \int_{V_i}^{V_f} \frac{nRT}{V-nb}-\frac{n^2a}{V^2}\:dV\\
    \end{align*} 

and here is what is displayed:

These are the packages being used:

\documentclass[12pt]{article}
\usepackage{physics} 
\usepackage{siunitx} 
\usepackage{enumerate}
\usepackage{graphicx} 
\usepackage{parskip} 
\newenvironment{calign}

The italicised "program@epstopdf" seems to appear out of nowhere and I'd appreciate some help in removing it. Thanks in advance.