How To Change FM Page Restriction Message

Code goes to your active theme’s functions.php file

add_filter( 'gettext', 'wpc_change_some_text1', 20, 3 );
function wpc_change_some_text1( $translated_text, $untranslated_text, $domain ) {
    if ( $untranslated_text === 'Sorry your are not allowed to access this page!' && $domain === 'wpcargo-frontend-manager' ) {
        return 'New text here 1';
    }
    return $translated_text;
}


add_filter( 'gettext', 'wpc_change_some_text2', 20, 3 );
function wpc_change_some_text2( $translated_text, $untranslated_text, $domain ) {
    if ( $untranslated_text === 'Please contact administrator for your permission.' && $domain === 'wpcargo-frontend-manager' ) {
        return 'New text here 2';
    }
    return $translated_text;
}