assign tasks to members

Hi Nasim - Thank you for reaching out to us. Please make sure that the members you are trying to assign tasks to have the permission to access your project first.

How to check: Please go the Members page of the project and see if the members are invited into the project.

Please also note that if the member was added to the Organization level as an Admin or Normal+ member, then he/she will have access to all the projects under that organization. This means that even if you don't invite the added member to the Project, you will still be able to see him/her in the assignee dropdown list when you try to assign the task. You can learn more about permission levels here and here. Hope this make sense.