I am having the same issue. I spoke with customer support yesterday and they said it was an issue they were currently working on and expected to have it resolved within hours. it is still not fixed. 

tried the incognito window, tried manually entering log in info, tried clearing cache. 

it is the same error 103. 

I have three bank accounts linked to my qbo, and 2 of them currently don't sync properly (I gave up years ago on paypal and download those transactions manually) it is beyond frustrating that I may have to do that for venmo as well...tho I am waiting hoping for resolution and don't want to create a bunch of double transactions.