Add an Account
Add a Storage Account SharePoint Site
Site URL is correct, Enter Account Name ignores entry and comes back to same screen
Adding account fails and there is no help on the Adobe help site
If this works, it should be available on all Adobe apps
Justin H commented
1. "Enter Account Name" is misleading because people think they should enter their account name for Office 365/SharePoint instead of the SharePoint site name. This is how they think Acrobat will authenticate with SharePoint, which brings me to the next item.
2. Relying on people to sign in to SharePoint from Internet Explorer (IE) with the stay signed in option selected to add a new site or to access an existing site already saved in Acrobat when the SharePoint authentication in IE has timed out causes the problem described above.
3. Finally, it is not clear what the URL should be. It should be just the URL path to the site (e.g., https://contoso.sharepoint.com/sites/Accounting) without a page name (e.g., home.aspx).
Clarifying the label for the site name entry field, changing the authentication method, and clarifying what the URL should be would help people with the OP's bug request.