Turbotax has no provision to attach an external PDF.
the signed 8283 must be submitted by mail with form 8453
Turbotax will generate the 8453 once the 8283 info is completed. according to Turbotax you should be able to e -file with a dummy 8283 that will be included in the e-file
contact support for how to e-file in your situation if you have continuing issues.
When and Where To File form 8453
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 73344-0254
