Steps to reproduce the issue

• SEF enabled

• Load a page: https://www.example.com/anytext.html

Expected result

Message according to language, for example, "404 URL inválida".

Actual result

"404 URL invalid"

System information (as much as possible)

Joomla 3.9.21

Additional comments

By searching for "URL invalid" in Joomla files, I found only one reference, line 238 of \libraries\src\Router\Router.php

`throw new RouteNotFoundException('URL invalid');`

That text is not translatable. I tried by adding the line URL invalid="URL inválida" in es-ES.ini file but no avail.

Notice that this happens only in route problem because the URL ends with html. If I write, for example, https://www.example.com/sfsfsdg the error shown is JERROR_PAGE_NOT_FOUND which is translatable.