To restrict a user from accessing the system you should disable his/her account. Complete deletion isn’t possible in order to have access to the historical data.
To do so, please follow these steps:
1. Go to User management (within the Configuration tab)
2. Find the needed user (you can use a filter for searching by name or other parameters)
3. When you have found a required user, you should click on the edit button.
4. Then you will see the “Edit User” menu. There is a switcher at the bottom of the main page, and you should click on it and then on the Update button. Now your user is disabled.
Please note that sometimes you can’t disable the user unless there are required actions from him/her, or she/he is a part of the approval process.
You can see that the switcher is grey and you can’t do anything with it. Also, there is a red information sign on the right. Click on it to know why you can’t disable the user.