How do I log into a secondary email account?

There's a couple of ways you can go with this.  One----you need to sign out of the first account before you can sign into the other one.  After you have done that, click on "Sign in" at the top of the page and then enter the credentials for the second account.  OR--------open a private browsing window in your browser, navigate to Xfinity.com again and then sign into the second account.  This treats it as a new  browsing session and is not affected by the other one if it's still open in the other window.

On a related note-------you can enable the secondary account as an external account within the first one by entering it in the section in the left folder pane where it says "Add mail account".  Once done, you don't have to worry about signing into it again. You can then access both accounts on the same page.   It's a mail fetcher similar to the ones found in Oulook.com, Gmail, and some other webmail programs.

Thanks for your reply.

I've tried the logging out and trying to log in with the secondary account name, it does the same thing -- when I enter the password it flips back to the primary account name.

I normally use a mailreader.  I've never tried to use webmail before. The secondary account I'm trying to log into is my main account ( the account I use the most ).  It works now and I'm afraid to do your second procedure fearing it will cause this account to stop working and, for me that would be a disaster.

Okay, I finally got it to work.  I had to change my password for the secondary account, though I have never changed it in 9 years.