Adding another data point, I also get an import unsuccessful error when attempting to import from Betterment using a Betterment app password. I'm using a downloaded version of TurboTax Premier 2019 for mac with the latest updates as of March 7, 2019.
The BIGGEST reason for purchasing TurboTax Premier 2019 is the ability to import from popular investment firms. As a customer, I don't care if it's a TurboTax or Betterment issue and I should not have to chase the issue down with Betterment myself. If TurboTax claims that it can import from Betterment, it is Intuit's responsibility to chase down Betterment and get the issue resolved regardless of who's at fault. Get your product manager & engineers to hop on the phone with your Betterment counterparts and hash it out. It's just importing software logic, not rocket science.
