When I set up 1&1 CNAME, then I can't add or edit MX change.

When I set up 1&1 CNAME, then I can't add or edit MX change.

I have a site hosted on 1&1 and am trying to set up an account, but when I enter the domain name jurugo.com I am requested to create a subdomain in order to set up a CNAME. Once I verified the the domain I added users, and then came to the part where I have to edit the MX exchange. The only problem is that I can't. I get the following message at step 5. See image below.

1. I made the subdomain as requested.

2. It's hosted on 1&1.

3. I'm stuck 

HELP!!!!!!