Generate .pem certificate with PHP for PayPal - ssl

Question

i need some help with the follow issue.
A multi user e commerce application uses .pem format certificates to encrypt paypal buttons, until now all certificates was generate with the Linux console with openssl commands.
So far everything works fine, but isn't a practical process if the client has many users, we want users can generate their certificates from their admin panel.
I found the follow script to generate the certificate:
$dn = array("countryName" => 'GB', "stateOrProvinceName" => 'State', "localityName" => 'SomewhereCity', "organizationName" => 'MySelf', "organizationalUnitName" => 'Whatever', "commonName" => 'mySelf', "emailAddress" => 'user#domain.com');
$privkeypass = '1234';
$numberofdays = 365;
$privkey = openssl_pkey_new();
$csr = openssl_csr_new($dn, $privkey);
$sscert = openssl_csr_sign($csr, null, $privkey, $numberofdays);
openssl_x509_export($sscert, $publickey);
openssl_pkey_export($privkey, $privatekey, $privkeypass);
openssl_csr_export($csr, $csrStr);
echo $privatekey; // Will hold the exported PriKey
echo $publickey; // Will hold the exported PubKey
echo $csrStr; // Will hold the exported Certificate
The output of this script generates me three blocks
-----BEGIN RSA PRIVATE KEY-----
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE REQUEST-----
-----END CERTIFICATE REQUEST-----
As a test, I copied the entire block ----- BEGIN CERTIFICATE ----- ----- END CERTIFICATE ----- and stick it in a text file with the .crt extension.
then I'll paypal account and try to upload the certificate, but PayPal tells me that the file is not in .pem format
The certificate you are trying to upload is not in the proper format. The certificate must be in .pem format.
Actually I have not much experience with ssl functions of PHP and so I turn to you, if anyone can give me some light over this issue, I appreciate it from now.

Answer 1

I've tested ran your code and sent the result to this verify page
https://www.sslshopper.com/certificate-decoder.html
Seems to generate a correct certificate if you just print the public key and test that.
Seems to be a difference in format between crt and cer for the keys though mainly due to encoding.
https://support.ssl.com/Knowledgebase/Article/View/19/0/der-vs-crt-vs-cer-vs-pem-certificates-and-how-to-convert-them
Test a different encoding or file extension.