new owner for ssl enabled site

[Polloxxp]

Dear,

We have a site for which we have a ssl certificate and an exclusive IP address associated with.
Now we want to change the owner for that site but we get a warning:
Unable to continue domain transfer: no domains selected, or selected domains already belong to the destination client
and on the next line: chown__ssl_already_used.

What's wrong here?

Thx
P.