In this case it is not PxPlus 2016. We actually have another background process on the same server executing the same code that the webserver process is executing and the *web/email call works perfectly in that process. So it's something different about the webserver process that I cannot figure out. I'm passing all the same values in the *web/mail call for the equivalent arguments of the *web/email call. I'm not passing any timeout value to *web/email and it's taking the full 60 seconds to fail based on the time stamps of the logging that we're doing.
This really is perplexing because it's a very simple text/html email with the server address, port 25 specified, from address, reply address same as from, one to address, a subject, and a very short message. No authentication, ssl, cc addresses, bcc addresses, or attachments.