could not load PEM client certificate, OpenSSL error for calling SOAP services in PHP

I have a wsdl API that uses from Certificate to answer. I have a certificate.cer file in base64 format I created a pem file with following commands:

1- openssl pkcs12 -export -out mycer.pfx -inkey mycer.key -in mercer.cer 

2- openssl pkcs12 -in mycer.pfx -out mycer.pem

and I write following code to use it:

        $curl = curl_init();
        $date = "2021/02/01";
        curl_setopt_array($curl, array(
            CURLOPT_URL             => 'url'
            CURLOPT_RETURNTRANSFER  => true,
            CURLOPT_MAXREDIRS       => 10,
            CURLOPT_FOLLOWLOCATION  => true,
            CURLOPT_HTTP_VERSION    => CURL_HTTP_VERSION_2_0,
            CURLOPT_SSL_VERIFYPEER  => true,
            CURLOPT_SSLCERT         => storage_path().'/certs/mycer.pem',
            CURLOPT_SSLCERTPASSWD   => '1234',
            CURLOPT_CUSTOMREQUEST   => 'POST',
            CURLOPT_POSTFIELDS      => "<x:Envelope xmlns:x=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:tem=\"http://tempuri.org/\">
    <x:Header/>
    <x:Body>
        <tem:GetAccountTransaction>
            <tem:accountNo>123</tem:accountNo>
            <tem:rowSeqPerDay>0</tem:rowSeqPerDay>
            <tem:transactionDate>{$date}</tem:transactionDate>
        </tem:GetAccountTransaction>
    </x:Body>
</x:Envelope>",
            CURLOPT_HTTPHEADER => array(
                'SOAPAction: http://tempuri.org/IStatementService/GetAccountTransaction',
                'Content-Type: text/soap+xml; charset=utf-8'
            ),
        ));

        $response = curl_exec($curl);

        curl_close($curl);
        dd($response , curl_error($curl));

But I get this error:

"could not load PEM client certificate, OpenSSL error error:02001024:system library:fopen:File name too long, (no key found, wrong pass phrase, or wrong file format?)"

My question is how can I call this special api type?