error when I try to validate unique field in Laravel

I'm trying to validate in Laravel as:

public function store(Request $request)
{
$validatedData = $request->validate([
'CurrencyName' => ['unique:tblcurrencies', 'max:50']
],[
'CurrencyName.unique' => 'err1!',
'CurrencyName.max' => 'err2!'
]); 
Currency::create([
'CurrencyRef' => Helper::GetNewRef(),
'CurrencyName' => $request['txtcurrencyname'],
'CurrencyPrice1' => $request['txtcurrencyprice1'],
'CurrencyPrice2' => $request['txtcurrencyprice2'],
'CurrentUser' => auth()->id()
]);
}

in the view file I inserted:

@if ($errors->any())
<div class="alert alert-danger">
<ul>
@foreach ($errors->all() as $error)
<li>{{ $error }}</li>
@endforeach
</ul>
</div>
@endif

and the form:

<form class="needs-validation was-validated" action="{{ route('currencies.store') }}" method="POST">
@csrf
<div class="row row-sm">
<div class="col-lg-12">
<div class="form-group row">
<label for="txtcurrencytype" class="col-lg-2 col-form-label">Type</label>
<div class="col-lg-10">
<input type="text" class="form-control" id="txtcurrencytype" name="txtcurrencytype" value="forg" disabled>
</div>
</div>
<div class="form-group row">
<label for="txtcurrencyname" class="col-lg-2 col-form-label">currency name</label>
<div class="col-lg-10">
<input type="text" class="form-control" id="txtcurrencyname" name="txtcurrencyname" placeholder="currency name" required>
</div>
</div>
<div class="form-group row">
<label for="txtcurrencyprice1" class="col-lg-2 col-form-label">price1</label>
<div class="col-lg-10">
<input type="number" class="form-control" id="txtcurrencyprice1" name="txtcurrencyprice1" step="any" required>
</div>
</div>
<div class="form-group row">
<label for="txtcurrencyprice2" class="col-lg-2 col-form-label">price2</label>
<div class="col-lg-10">
<input type="number" class="form-control" id="txtcurrencyprice2" name="txtcurrencyprice2" step="any" required>
</div>
</div>
</div>
</div>
<div class="modal-footer">
<button class="btn ripple btn-primary" type="submit">save</button>
<button class="btn ripple btn-secondary" data-dismiss="modal" type="button">cancel</button>
</div>
</form>

but the record is saved (even if I enter duplicated currency name) and redirects me to the same page but as white page!!
I tried to solve this but I couldn't

and that's the model file:

namespace App\Models;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
class Currency extends Model
{
use HasFactory;
protected $table = 'tblcurrencies';
protected $fillable = [
'CurrencyRef',
'CurrencyName',
'CurrencyPrice1',
'CurrencyPrice2',
'CurrentUser',
];
}

I think you just have slight differences between what the name properties on the form are and what your validator is expecting.

The array key is going to have to match the name field here:

<input type="text" class="form-control" id="txtcurrencyname" name="txtcurrencyname" placeholder="currency name" required>

But your rules array is telling the validator to check against an input named "CurrencyName".

Adjust the validator array or the input name properties so that they match up accordingly.