Latex stops referencing theorem environment

Question

I'm resuming a project after some weeks.

Now, when I reference some theorem, the result are that bored question marks (??). For theorems that already exists, refence to that works well, but referencing other theorems doesn't.

It's weird. Before all was fine.

For example:

\begin{def:conv_method_1}

...

\end{def:conv_method_1}

...

Theorem~\ref{def:conv_method_1}

and the result is

Theorem ??

Any trick?

Answer 1

I think your theorem definition should say \begin{theorem}\label{def:conv_method_1} ... instead of \begin{def:conv_method_1} ....