Error text in an array is not translated, if polylang is activated

More information would be needed to help you. Where does this code come from? A plugin? A theme? Is it freely available?

Sorry you are right.
It is a new plugin not published yet, programmed by myself.

This error array is filled in a function and than

$err_mess = '';
foreach( $error as $err ) {
	$err_mess .= $err . '<br />';
}
$this->message .= '<p class="wpsmnt_error">'.$err_mess.'</p>';

And than echoed in a second function on the frontend?
echo $this->message;

What I do not understand is, if I deactivate polylang it is translated?

What I do not understand is, if I deactivate polylang it is translated

That’s strange indeed.

How do you load your texdomain? Did you make sure that you load it in a function attached to a hook and not as soon as th plugin is loaded?

This sounds like a possibility…
My textdomain is loaded in the

private function __construct() {
add_action( 'plugins_loaded', array( $this, 'load_plugin_textdomain' ), 1, 1);

and

public function load_plugin_textdomain() {

load_plugin_textdomain( 'wpsmnt_', false, dirname( plugin_basename( __FILE__ ) ).'/lang/' );
}

You suggest it should be in a hook?

It’s correct to put it in the ‘plugins_loaded’ hook. Could it be the that the domain is not the same? I read ‘wpsmnt_’ here and ‘_wpsmnt’ in your error text. If that’s not the issue, maybe you can try to decrease the priority from 1 to a bigger value.

Thanks again, but it did not help
It was a typing error (here in the forum) the domain is both: ‘wpsmnt_’
I checked every priority from 1-10 no difference?

I just checked if
_e( 'Price', 'wpsmnt_' );
would be translated at this point in the function.
Same issue if I deactive polylang, it works.

It is a mystery for me? Any more ideas?

Sorry some times I am so slow…

Are you setting the language from content? If yes, the language is defined quite late in a function hooked to ‘wp’ action (with priority 5). So if you store strings in a variable before this action has been fired, they won’t be translated.

If the language is set from the url, then it is defined as soon as possible in ‘plugins_loaded’ with priority 1.