Not sure what you mean by that number.
When you log in and go to the 2016 Tax Timeline, is there no evidence you had filed a 2016 return, and it's acting like it wants you to prepare a new return?
I don't know what product you are using. There is no extra fee to fix and resubmit a rejected return. I can help you find the return. You probably have multiple accounts and signed into the wrong one. I'll leave you the steps below to find the account that has your 2016 return.
If you prepared a 2016 online return, but see no evidence of it when you log back in, then you likely have multiple accounts and signed into the wrong one.
To get a list of your User IDs and recover account access, you can use the tool at the link below. Try using your phone number first. If you try using your email address, and you have more than 1 email address, you should run the tool on each one.
NOTE: Before running the account recovery tool below, log out of all Intuit accounts including this user forum, or you might end up in a loop. Then clear your browser Internet cache, close your browser, then reopen it, and go to the link below. You may wish to copy this link so you can paste it into the new browser session.
https://myturbotax.intuit.com/account-recovery
If still no luck after running that on your phone number and each email address you have, then run the tool yet again, but this time choose the small blue link that says "Try something else", and it will look you up by SSN and other parameters.