Wp-calypso: Login: Jetpack Connect flows require retries with the new login

[tyxla]

With the new Calypso login, when attempting to go through any Jetpack Connect flow as a non-logged in user, the connection flow will fail after a couple of automated retries and will prompt for a manual retry. After retrying, it succeeds in connecting, and redirects to the plans page as expected.

With the old wp-login, no retry is needed.

To reproduce, make sure you are testing on staging (proxied) and:

• Make sure you're not logged into WordPress.com.
• Go to https://wordpress.com/jetpack/connect/
• Input the URL of a fresh Jetpack site (new, clean .org site with Jetpack installed and activated that has never been connected) in the connection form.
• You are presented with the signup form. Click the login link at the bottom.
• You'll be prompted to log in (the new login form). Do it.
• Connection flow continues, and you'll see it retries automatically, then fails, prompting for a new manual retry.
• Try the above steps for production (non-proxied). The retry will not happen.

cc @fabianapsimoes @stephanethomas

[stephanethomas]

I was able to reproduce this issue in development on master setting the following in the browser's console:

localStorage.setItem( 'debug', 'calypso:jetpack-connect:*' )

It looks like this a problem with the _wp_nonce sent to the /jetpack-blogs/:site_id:/jetpack-login API endpoint:

calypso:jetpack-connect:actions Trying Jetpack login. +39s
calypso:jetpack-connect:actions Authorize error +228ms Error: Could not verify your request.
calypso:jetpack-connect:actions retrying auth +14ms
calypso:jetpack-connect:actions retryAuth +11ms

The Could not verify your request error is indeed returned by the API with not_verified as error code (which is very easy to locate in our server code since it's the only occurrence). I'll keep investigating tomorrow to identify the root cause.