Stripe has upgraded their API servers to only accept requests made using the new TLS 1.2 encryption protocol.
You can read more about this in their announcement.
Ask your web host or server admin to make sure your server supports TLS 1.2.
Your server should:
- Run OpenSSL 1.0.1 or higher, or another cryptographic library that supports TLS 1.2
- Run PHP version 5.5.19 or higher.
- Run cURL version 7.34.0 or higher.
While the best solution is to upgrade your server, you may be able to force TLS 1.2 for PHP and cURL via the following code snippet:
Please note that this may not work and that you will have to update this if, at any point in the future, TLS 1.2 is compromised or a new version is required by Stripe.
There’s a free WordPress plugin you may wish to utilize which will help you determine whether or not you need to upgrade your server and also contains an option to force TLS 1.2 as per the above code snippet.
While this plugin does not contain an endpoint specific to Stripe, it will help diagnose potential issues.