there are a couple of things I've found. First, I've found this post from @kabirdis stating that Oauth1 currently doesn't support user-based authentication (Nov 22 - Pass xml data to rest api - #2 by Kabirdas).
The OAuth 1.0 flow we offer doesn't support user-based authentication at the moment. A couple other members of the team have been investigating this particular connection with etrade and, unfortunately, we don't have a working solution. It is something the dev team will take a look at and we can let you know here when it's included!
I remember reading somewhere that some requests are sent sandboxed from a different server resulting in different origin addresses and XSS errors? Otherwise the only other thing I could find is a stackoverflow topic where OP was getting this error in Postman, which you actually have working but there were a couple replies that I thought could be relevant (postman - Getting 401 from Netsuite REST API - Stack Overflow)
- realm (your account id, if using a sandbox, make sure the realm looks like
1234567_SB1, with an_and not a-)
...For me, the role I was assigned to did not have permissions to Rest Web Services in Netsuite.