My organization just enrolled for O365 and have enabled SharPoint for creating sites. I have created a Site Collection and am the primary Site Collection Owner of the site. However, when I try to open the site in Designer, it asks for credentials. When I provide my organization's credentials, it says incorrect credentials. When I provide my live account credentials, it does not accept it and asks me to re-enter the credentials.
Previously it gave me an error "This feature has been disabled by your administrator". I did a registry hack and the error was gone.
Please let me know if there are any settings that need to be done at the O365 admin level to allow opening sites in SPD. At the site level, I have already enabled opening sites in SPD.