Graceful timeout handeling

[MultiSuperFreek]

A customer of ours got alerted by customers of his shop, that they weren't allways receiving their digital products. After some digging I found this in the plugin logs:

cURL error 28: Operation timed out after 5000 milliseconds with 0 out of -1 bytes received

Since I use Postmark (and by extend this plugin) for the reliable delivery, this is no good. I was hoping this plugin would do better than the regular SMTP service, and maybe retry or use a (way) longer timeout, so that delivery can be (better) garanteed.

[37Rb]

We just experienced this as well. For the past day or two about half of our outgoing emails have been timing out after 5 seconds and we had no idea. I had to hack the plugin and increase the timeout as a work around. This is a disaster on an ecommerce site! Quite a few people didn't receive order confirmations.

1. Retrying would be nice, maybe with a longer timeout.
2. The timeout should be configurable in the plugin.
3. If emails are failing there should be a big error notice for admins to see on every admin page. How often are admins staring at the postmark wordpress plugin logs?