I happened to face the same issue and this is not yet resolved I suppose.I haven't checked but this was the working around i used and I could see you are doing that.
Refer to this
Which of the workarounds mentioned in your linked article worked for you?
1. not using the iphone app
2. embedding credentials in the workbook
3. turning off automatic sign-in on tableau server
None of these seem satisfactory to me.
turning off automatic sign-in on tableau server worked for me.
Which version of tableau are u using.I am using Tableau 9.1
We are using 9.3.
We are facing the same issue and turning off automatic sign-in on tableau server did not solve anything.
We are using Tableau version 10.2