Error: array_flip() expects parameter 1 to be array, string given

I am new to Laravel, getting the following error,

array_flip() expects parameter 1 to be array, string given

in GuardsAttributes.php line 188
at HandleExceptions->handleError(2, 'array_flip() expects parameter 1 to be array, string given', '/Users/aaronmk2/Desktop/CodingDojo/php/onetoone/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Concerns/GuardsAttributes.php', 188, array('attributes' => array('name' => '2250 nw 59st Seattle, WA 98107')))
at array_flip('name') in GuardsAttributes.php line 188
at Model->fillableFromArray(array('name' => '2250 nw 59st Seattle, WA 98107')) in Model.php line 216
at Model->fill(array('name' => '2250 nw 59st Seattle, WA 98107')) in Model.php line 145
at Model->__construct(array('name' => '2250 nw 59st Seattle, WA 98107')) in web.php line 24

Here is the code that is creating the problem

Route::get('/insert', function(){
    $user = User::findOrFail(1);

    $address = new Address(['name' => '2250 nw 59st Seattle, WA 98107']);

    $user->address()->save( $address);
});

What is the issue and how can I fix it.

via Aaron