Save new entities error help me to solve this

Controller
$data = $this->request->data;
$entities = $table->newEntities($data[‘configuration’]);
debug($entities);
exit();

        if ($table->saveMany($entities)) {
            $this->Flash->success(__('The configuration has been saved.'));
            return $this->redirect(['action' => 'prefix', $prefix]);
        }else {
            $this->Flash->error(__('The configuration could not be saved. Please, try again.'));
        }

Output:-
\src\Controller\Admin\ConfigurationsController.php (line 84)
[
(int) 0 => object(App\Model\Entity\Configuration) {

	'input_type' => 'text',
	'name' => 'Social.linkedin',
	'value' => '',
	'[new]' => true,
	'[accessible]' => [
		'name' => true,
		'value' => true,
		'title' => true,
		'description' => true,
		'input_type' => true,
		'editable' => true,
		'weight' => true,
		'params' => true
	],
	'[dirty]' => [
		'input_type' => true,
		'name' => true,
		'value' => true
	],
	'[original]' => [],
	'[virtual]' => [],
	'[errors]' => [],
	'[invalid]' => [],
	'[repository]' => 'configurations'

},
(int) 1 => object(App\Model\Entity\Configuration) {

	'input_type' => 'text',
	'name' => 'Social.skype',
	'value' => 'rajeshbansal23',
	'[new]' => true,
	'[accessible]' => [
		'name' => true,
		'value' => true,
		'title' => true,
		'description' => true,
		'input_type' => true,
		'editable' => true,
		'weight' => true,
		'params' => true
	],
	'[dirty]' => [
		'input_type' => true,
		'name' => true,
		'value' => true
	],
	'[original]' => [],
	'[virtual]' => [],
	'[errors]' => [],
	'[invalid]' => [],
	'[repository]' => 'configurations'

},
(int) 2 => object(App\Model\Entity\Configuration) {

	'input_type' => 'text',
	'name' => 'Social.googleplus',
	'value' => 'https://entities.com',
	'[new]' => true,
	'[accessible]' => [
		'name' => true,
		'value' => true,
		'title' => true,
		'description' => true,
		'input_type' => true,
		'editable' => true,
		'weight' => true,
		'params' => true
	],
	'[dirty]' => [
		'input_type' => true,
		'name' => true,
		'value' => true
	],
	'[original]' => [],
	'[virtual]' => [],
	'[errors]' => [],
	'[invalid]' => [],
	'[repository]' => 'configurations'

},
(int) 3 => object(App\Model\Entity\Configuration) {

	'input_type' => 'text',
	'name' => 'Social.facebook',
	'value' => 'https://www.facebook.com/theweblogic',
	'[new]' => true,
	'[accessible]' => [
		'name' => true,
		'value' => true,
		'title' => true,
		'description' => true,
		'input_type' => true,
		'editable' => true,
		'weight' => true,
		'params' => true
	],
	'[dirty]' => [
		'input_type' => true,
		'name' => true,
		'value' => true
	],
	'[original]' => [],
	'[virtual]' => [],
	'[errors]' => [],
	'[invalid]' => [],
	'[repository]' => 'configurations'

},
(int) 4 => object(App\Model\Entity\Configuration) {

	'input_type' => 'text',
	'name' => 'Social.twitter',
	'value' => 'https://twitter.com/rajeshbansal4u',
	'[new]' => true,
	'[accessible]' => [
		'name' => true,
		'value' => true,
		'title' => true,
		'description' => true,
		'input_type' => true,
		'editable' => true,
		'weight' => true,
		'params' => true
	],
	'[dirty]' => [
		'input_type' => true,
		'name' => true,
		'value' => true
	],
	'[original]' => [],
	'[virtual]' => [],
	'[errors]' => [],
	'[invalid]' => [],
	'[repository]' => 'configurations'

}

]

Error:-
Error: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry ‘Social.linkedin’ for key ‘key’

Check you DB schema, it seems you only allow unique values for ‘name’(‘key’?).