Need Help with Redmine

I can`t use redmine task server in idea, because i have next error(see screenshot).
I input next data:

URL - url addres of server (ex http://redmine.test.com)
Username - my login
Password - it rather clear:)
Project ID - keyword from project settings page
Api Token - nothing. What i must write there ?

Is it right ?

When i press test button i have error(screenshot)