# Error: “No shape named tikz@f@1-1-2 is known”

I typed:

\begin{tikzcd}
E \arrow[r] E
\end{tikzcd}


and I get the error "No shape named tikz@f@1-1-2 is known." I have tried many things and don't know how to fix this.

The syntax of tikz-cd requires nodes to be separated by the & symbol. Here's a minimal document. For future questions, it's really helpful (and usually essential) to add such a document to your question (even if it yields an error.) See I've just been asked to write a minimal example, what is that?.
\documentclass{article}