I get the following error when attempting to activate the JetPack plugin on my WordPress instance I have running on Heroku.
Jetpack could not contact WordPress.com: register_http_request_failed. This usually means something is incorrectly configured on your web host. Operation timed out after 15000 milliseconds with 0 bytes received
I found a claim that Heroku blocks this type of business-to-business traffic but couldn't find any documentation to support the claim.