If you receive an error when inviting users to collaborate in Condens, the error message might be as follows.
A person’s email address can only be part of exactly one organization account in Condens. So if you receive that message this person already has a Condens account somewhere else.
There are three ways to handle this:
Delete existing user account: Ask the person you want to invite to delete their existing user account, so you can invite them to your organization. They can do so by going to Settings → Profile → Delete my user account. Please note that they will lose access to the current account including the data stored with it.
Use a different email address: Ask the person if they have a second, different email address you can use to invite them to Condens. That way they can stay part of the other account they are in.
Create an alias: If the person doesn't have a second email, they might create one. With some email providers like Gmail or Microsoft Exchange Online creating an alias is easily possible by modifying the email address. There are also services like SimpleLogin which let you created aliases for free.