Sprintr Invite outside company

We are doing a project with sprintr in which i want to add a customer to our project. However, the customer already has a MxID and i found no option to add a person from a different company to your project. To bypass this i tried to invite the customer using his email address. But because the customer already has an MxID this does not work either as it conflicts with his new MxID. So how can i invite externals into our project?
1 answers

He has to accept the sprintr invitation and perform a signup, which is the third in in his invitation email.


He did that, but someone else already 'claimed' the company, we will resolve the issue.