These two warnings sound like perhaps you've accidentally used the + operator instead of the concatenation operator ., but as marto said, you didn't actually show the code that's causing the error. As for why it's giving you a "500 Can't connect to ipnpb.sandbox.paypal.com:443", I'd suggest trying to connect to that URL using curl and writing a simple command-line script using LWP::UserAgent to connect to that server, and debugging that.