The left hand side of the tr is not a regular expression. Just include a real space in the character list.

$ perl -E '
> @data = (
>    q{Hello, world!},
>    q{te-st%$/*.},
>    q{All_of_this_is_OK.},
>    q{!@#$%^&*()12345},
>    );
> say for map { tr{A-Za-z0-9_. -}{}cd; $_ } @data;'
Hello world
te-st.
All_of_this_is_OK.
12345
$
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