probably not Turbotax but your firewall/antivirus. Sometimes, temporarily disabling them works. Other times, using a different browser. Or you may ned to clear the cache on your browser. There other possibilities. the mail-in option mentioned by @fanfare requires completing Form 8453, which Turbotax supports. Print it our a
When and Where To File
If you are filing your tax return using an online provider,
mail Form 8453 to the IRS within 3 business days after
you have received acknowledgement from your
intermediate service provider (ISP) and/or transmitter that
the IRS has accepted your electronically filed tax return. If
you don’t receive an acknowledgement, you must contact
your intermediate service provider and/or transmitter.
Mail Form 8453 to:
Internal Revenue Service
Attn: Shipping and Receiving, 0254
Receipt and Control Branch
Austin, TX 73344-025
