Backup Copy - Offline and SMTP error

I made a backup copy from DC Android. In Ubuntu desktop, I imported the backup copy and, when I try to send a message, I am offline and see an error (image here)

But, if I use a new account with the same email I have in Android DC, everything runs well, except I don’t have “android app” contacts in my desktop account.
I don’t know. It’s a bug, or am I doing something wrong?