First I want to say, this adobe system is so great!
Nevertheless, greatness brings problems...
I have a webcommerce monthly and a muse monthly.
I have the oxo theme preinstalled and (would like to keep it as a template; already duplicated it) and want to upload my Muse theme. When I go to publish in the Muse menue, the following happens: the domain <blank> I chose is doubled like domainbusinesscatalysrcom.businesscatalyst.com and the system says:"The validity of the site domain.businesscatalyst.com could not be verified. The site may not exist, or you may not be an authorized user of this site. Choose another site and try again."
Choosing another site is not possible, because I need the features of the webcommerce.
Little Help! from the forum to work it out is required.
solution of the problem was provided from Adobe Sales Support: The Muse site that shall be uploaded to BC must be the same account like the BC account. I signed Muse before the trial ended, but I did not deactivate the trial site. I deactivated the Muse trial and could upload the .muse to BC smoothly.