Can I enter my Dropbox account with the auth code? I've lost access to my email address.

Hey billzink​, welcome to the commmunity!

I'd recommend getting in contact with our support team directly to look into this matter in more detail.

You can do this by opening an incognito/private browsing window, while not signed into your account, and accessing this link. 

From there you should be able to contact support. Make sure to pick an email to which you can receive and send emails from.

Thanks for posting on our Community today, billzink! Welcome aboard. 

It sounds like the dual authentication code you’re being asked for is the 6-digit code mentioned here. In this case, it's not possible to turn this requirement off due to security reasons.

Besides logging a ticket with the steps Dell mentioned above, can you also take a look at this Help Center article’s section and let us know if the provided suggestions help at all?

Hi billzink!

Just following up to check if you had a chance to review our last message.
If you still need assistance, feel free to get back to me with the details requested. If the issue is resolved, we'd love to know what worked out for you.