My customer is unable to opt in following invite to Email Contacts?

If configured for your retailer you will be able to add customers to your Contacts and then chat with them anytime via email. You will continue to chat through the Store App, but they will send and receive messages over email. If you invite a customer through an online chat it is up to them which of the available channels they choose to be added to. After adding your customer they will need to complete opting in before you can chat with them. The app will show the opt in status of the customer so you will know when you can start chatting.

For your customer to accept the invite they will need a valid email address and must not be in the Contacts list of a colleague in the same team as you. If they are having trouble opting in then you should contact Klarna Virtual Shopping support with the details of the chat and the customer and we can investigate.