Try downloading it using a different browser.  I only found this FAQ.  Maybe the workaround will work for your situation 

https://ttlc.intuit.com/community/tax-topics/help/turbotax-advantage-we-re-hitting-a-snag-error-when... 

If you continue to get this message, please attach a screenshot to this thread so we can assist you! 

Still getting this message over and over again.

I keep getting the message: Whoops, We hit a snag loading your data.    HELP

I am a victim of identity theft Bank Of America told me I had two payments one was in the amount of $13,131.09 and the other one was $5058.14. Two different cars went to two different places. One was in Yuma that address was [removed address].I’ve also taken loans out in my name I have 25 credit cards they took out of my name their loans they have taken out of my name

Ran into the issue on chrome, was able to download on edge browser