Random E-Mail adresses can request tickets in our Service Desk when sb shared an issue with them.

[jonas.mayer]

We got the following problem:

When a customer of ours created a ticket, he can share it with an email adress of his choice. So far, so good.

 This email adress now gets a message with an invitation to our Service Desk (project). By clicking the link, they can set up an account and then create tickets for us, even if we never added them to the project.

We want to prevent external users from using our project. Is there a way to avoid that external users can create an account on our Service Desk Entity w/o our knowledge? 

[Jack Brickey]

You can’t have it both ways. You can’t allow customers to include non-customers but prevent non-customers from joining. This is controlled under project settings > customer permissions.