Sometimes, the footer goes up in some pages.
So here is the page where I have the problem :
And here is the page that comes just after, and with a normal footer :
I am using the package fancyhdr in my document :
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhead{}
\fancyhead[C]{\leftmark}
\fancyfoot{}
\fancyfoot[C]{\thepage}
\renewcommand{\headrulewidth}{0.4pt}
Can anyone tell me why I am having this problem please, and how can I fix it.