Cannot assign a task to a new team member

I am trying to assign a task to a new team member and I am getting an error message: Server request error Request failed with status code 400. [Name of Team Member] permission can not be added because it will conflict with parent task permissions.

Hello Dave,
Welcome to Hitask!
Do you use the web, desktop or mobile app?
Please check the permissions of the Project this task belongs to, is it shared with person you’re assigning task to?

I use the desktop version. Where can I see the permissions?

Click on the task and then click Edit button. You will see the permissions and assignee options.

I use the desktop version. Where can I see the permissions?

In desktop version it’s the same. Click on a task and then click on Edit button.