Why is an untranslated string not showing up? In my module I have some custom strings. I use these in the t() function.
When I go to admin/config/regional/translate/translate and filter the untranslated strings my custom strings do not show here.

What could be going wrong?
The strings needs to be rendered a first time on a page in the not default language and your string keys will be visible in the Translate interface.

An important detail, the search is case sensitive. For example My text is different than my text.