Why can't I checkout without logging in to the Wordpress site?

This solution article is exclusively for Wordpress' Chargebee plugin users

It is not possible to check out as a guest since login is necessary to identify the customer. This facilitates Chargebee plugin to add a new subscription to the existing customer by passing customer ID in the API call instead of creating a new redundant customer in Chargebee.

Creating multiple subscriptions with the same email ID will result in multiple redundant customers inside Chargebee. To avoid that, Customer ID is obtained from Wordpress users' profile and consequent subscriptions will be attached to it. This will enable the customer portal to display a single email ID(single customer) with multiple subscriptions.

An example is given below for further clarification,

When login is not used:

Subscription 1

• Subscription created for example@example.com

• Customer created with ID - 2smoc9B3R2gBdVGQfI

Subscription 2

• Subscription created for example@example.com

• Customer created with ID - Hr5515PR2fvq58MTl

Showing both subscriptions in the customer portal for example@example.com is not possible.

When login is used:

Subscription 1

• Subscription created for example@example.com

• Customer created with ID - 1mkVvxVR1dvz11LC3

Subscription 2

• Subscription created for example@example.com

• Same customer ID(1mkVvxVR1dvz11LC3) will be used instead of creating a new one.

Both the subscriptions will be shown in the customer portal.