I have no problem signing on. Check your internet and try again 

I have no problems signing on either.  I can log in and view all of my different client accounts and the documents they have uploaded.

As my original post stated, the error only occurs when I attempt to upload documents myself.  I am still getting the same message this morning:

Getting the same thing for the last two days

Same issue here since yesterday - anyone hear of a fix coming?

I just tried logging in from a dummy client account I created several years ago and I am getting the same error message when I attempt to upload a document..  So this appears to be an issue impacting everyone -- an inability to upload any documents.  However, if I am responding to a client template sent by the accountant, I do have the ability to upload documents in response to specific questions.

Is Intuit working on this problem?  Tax season starts on Monday and clients want to upload their documents this weekend!

Yep, same for me!  Glad this outage did not last the entire weekend!