Hello,
Sorry, I misread your post. I thought you had the error in "Edit initial view" instead of "Edit Query Spec".
I would say the issue is with the universe itself. Maybe something is wrong in it ?
I remember we had an error like this with a erroneous SQL statement in the Universe ... But not totally sure.
Can't help more unfortunately 
That's a good idea to eliminate the need of users declared in Hana, as well to simplify the security. Thanks for answering.