If you have no errors on final Review / Smart Check, the e-file transmission error may be due to a large attachment, typically Form 8453 (Transmittal for e-File). Check the file size of this signed form PDF (or any other attachments). Generally, any file over 1-2 MB may cause a transmission error. TurboTax will convert an overly large file into an image, which you can see if you check your attachments. Reduce the file size (see link below) and replace the uploaded file.
You might also need to close other windows that are open, especially programs that are resource intensive.
Additional Information:
@Vickie0127
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
