This article will is designed to help if you go into an estimate and up the top you have a client, and a quote, but the lead is not assigned. This means there is no lead linked to the estimate and you hence can't use things like the client portal.
It's pretty easy to fix, before you start the below steps please ensure you have created a lead for the customer.
Important: the lead must be for the exact same client (in my case Dan C) or the linking wont work.
In the 'Estimates' section open the estimate/quote you want to link to and click on the 'Estimate Details' tab. Scroll down the the 'Lead Details' area.
Click 'Link to a Lead'.
The 'Select a Link to a Lead' pop out will appear to the left of the screen. Select the existing lead you want to link and click the "Link" button at the bottom.
Your lead in now linked to you estimate.