Logging in gives me a login form. How do I fix this?

I just finished fixing the problem that *.tradingpits.net was not pointing to our WP multisite. I had already added tradingpits.net under the Settings for MultiDomain, which is what told me I had to add a DNS record for *.tradingpits.net. So that's done now. I then created a new site under Sites in the Network Admin account, http://www.tradingpits.net. This created the user www and I entered my email as the admin email, so I got this email:

Your new site has been successfully set up at:

You can log in to the administrator account with the following information:
Username: www
Password: [redacted]
Log in here: http://www.tradingpits.net/wp-login.php

We hope you enjoy your new site. Thanks!

... But when I tried following those instructions, I was sent to this page, which has the same login form I had just filled out: http://www.tradingpits.net/wp-login.php?redirect_to=http%3A%2F%2Fwww.tradingpits.net%2Fwp-admin%2F&reauth=1

I verified that the site knows I'm entering the correct password because if I enter something else, I get the normal "ERROR: The password you entered for the username..." page.

Did I set something up incorrectly?