Certificate Verify Failing (Ruby on Rails: paypal-sdk-rest gem)

[Houdi]

Hi,

This afternoon calls to the PayPal api using Ruby on Rails 6 and the paypal-sdk-rest gem have begun failing with:

SSL_connect returned=1 errno=0 state=error: certificate verify failed (unable to get local issuer certificate)

I've updated the root certificate bundle (Redhat EC2 instance) but its made no difference.

Can anyone please suggest what to try next - we are currently unable to accept any online payments as a result.

Thanks