Hi there, @Jakob1… if I understand your post correctly, I think the first workflow should work if you ban a user and then they try to navigate to a new page. However, it seems to me like you need to add the log out and go to index steps to the workflow in which you are setting the user’s ban field to yes. So, set the field to yes, and immediately log the user out and send them to the index page. Have you tried that already?
Okay, I just tested this and it appears to work. Create a workflow using the Do when condition is true workflow event, add a condition to the event so it runs only when the user’s ban field is set to yes, set the event’s Run this field to Every time, and add actions to the event to log the user out and go to the index page.