Need to change email address

Hello,

I need to change the email address on my account.  When I changed it in my Adobe ID, then logged into Adobe sign, I got these 2 error messages (see 2 pictures below).  After about an hour, I change my email address back and it works again.  How can I change it?  (By the way, when I log in, click the question mark at the upper right and click 'Contact Support' (see picture), it asks me to login, which I do, then when I scroll down and click 'Start Now' under 'Contact Us' (see picture), it takes me to another page that asks me to Sign In, and I'm in an endless loop.  So I posted here.