Cannot activate Jetpack on my server

You may not have enough processes running.

To test, try creating a file sleeper.php:

<?php
sleep(5);
echo "Working fine\n";

And then run this from the cli:

curl -m 6 http://example.com/sleeper.php & curl -m 6 http://example.com/sleeper.php & wait

If there is only one process it will print out something like this:

Working fine
curl: (28) Operation timed out after 6001 milliseconds with 0 bytes received

Notes/credits: I received this test from my colleague Pyry Hakulinen while working on WordPress.com support. It should work as a basic test and starting point to troubleshoot the “Operation timed out after 15001 milliseconds with 0 bytes received” error.