"Unable to sign data." error on windows server

When you say `$config` do you mean `$options['config']` with the path to the openssl.conf file as described in https://www.php.net/manual/en/function.openssl-csr-new.php ?

Given the same config file is used to generate the key in the same function, passing the same file path to the export explicitly should be fine.

My thougths exactly.

Thanks. I've updated null to NULL.

Merged, thank you very much :-)