I have a site that is currently running CartThrob v2.7 and using "Paypal Website Payments Pro" for the gateway. I need to make some updates to the checkout process, and tried switching the gateway to "Sandbox" mode. However, when I do that and try checking out, I get a "SSL connect error (35)" error.

The checkout process works when the gateway is in "Live" mode (but obviously, that won't work for development.)

AFAIK, all of CartThrob's PayPal credentials are correct and up-to-date, and the PayPal account is in good standing. I know that "Paypal Website Payments Pro" is a legacy product, but switching to another gateway is not currently an option.

Any ideas?

1 Answer 1


(I'm with Vector; we're the people behind CartThrob)

You're almost certainly running into an issue because of PayPal's SSL certificate upgrades. You can find more information on that here: https://www.paypal-knowledge.com/infocenter/index?page=content&widgetview=true&id=FAQ1766&viewlocale=en_US&direct=en

PayPal upgraded their sandbox first but their live endpoints are getting upgraded soon, which will likely break all transactions on your site.

Compatibility with this change is completely controlled by your host and not something CartThrob or ExpressionEngine can control. Your host needs to upgrade the version of cURL used by PHP on the server. You should be able to send them the above link.

If you're on an unsupported host/server and need help doing it yourself, or want us to verify that your host did it correctly, feel free to get in touch! We're [email protected].

  • Thanks for the quick response. I've contacted the hosting provider about upgrading cURL. I'll let you know what happens. May 31, 2016 at 0:53
  • That seems to have fixed it. Thanks for your help. Jul 12, 2016 at 12:34

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