openssl_sign(): Supplied key param cannot be coerced into a private key

[VicRejkia]

I implemented this package in my Laravel project and initialized it like this

            $client = new Spot([
                'key'  => config('binance.testnet.api_key'),
                'privateKey'  => config('binance.testnet.api_secret'),
                'baseURL' => 'https://testnet.binance.vision'
            ]);

a simple $client->time() returns the timecode. But if I want to send an order or want to get some account info, I will get this error:
openssl_sign(): Supplied key param cannot be coerced into a private key

What do I wrong?

[2pd]

can you provide more details of the error message?

privateKey should be the private key file path in the client side.