When you say it updates successfully manually do you mean by performing a "Run Now" refresh in Tableau Online or a manual refresh in Tableau Desktop?
The error you are getting appears to be an error coming from Redshift
Yeas, I mean "Run Now" in Tableau Online.
I've read about this error. The most interesting case for me is the difference between schedule updating and "Run Now": why it crashes in the 1st case and update in the 2nd?