unable to sign in

when I log into echosign I get a pop up about the price increases. I click the Buy Now button and it takes me to a log in page only it won't accept my email  – it's entered automatically, in grey, but will not allow me to edit it or move forward - there's a red tricngle with an exclamation mark next to it. It IS my correct email address that I use to log into echosign. I cannot change it. I cannot move forward. I've tried using Safari and firefox on my mac, and whatever the default browser on a windows 10 pc is. Same thing.