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This is a known issue and Tubrotax will not fix it because they don't care.
Get a refund, that's what I've done.
https://ttlc.intuit.com/community/taxes/discussion/re-1099b-freezing/01/2149628#M773467
This is not the issue. I tried 4 different computers and 2 different browsers on each computer and still same thing. Rotating circle on each computer and browser as well as my phone.
If all of those devices were using the same internet connection then I would suggest trying a different internet connection.