When purchasing JuiceSSH Pro, you will need to select a Google email address that the purchase will be linked to. This will allow you to easily activate your purchase on any other devices you own (or might buy in the future) by using the I've Already Purchased button.

If you don't see any email addresses listed, this can be caused because you have revoked Android permissions from JuiceSSH. In order for JuiceSSH to be able to list your possible email addresses, it needs access to the Contacts permission group.

In order to restore permissions to JuiceSSH, go to your main Android Settings page -> Apps -> JuiceSSH -> App Permissions and ensure that all requested permissions are granted.

Please note, JuiceSSH will never actually read your contacts.

This is just due to the way Google bundle their Google Authentication permissions into the broad Contacts group. 

For a full run down on every permission requested by JuiceSSH, and the exact reason we request it, please see: