# Help:FAQ/Technical questions/Problem with Eqn template

What's probably happened is that you have included instances of {{ or }} or | in your $\LaTeX$.
The MediaWiki template parser takes precedence over the MathJax one, and views {{ and }} as the beginning and end of the invocation of eqn, thus breaking the $\LaTeX$ in two. Similarly, it interprets | as the MediaWiki instruction to interpret what follows as a parameter value.
1. Put a conventional space between all instances of {{ and }} to make them { { and } }
1. | with \vert
2. || and \| with \Vert, which renders as $\Vert$.