Connection to synchronization server failed

Hi All,

just upgraded TIH to version 2015 (build 6525, German version for 3 computers). All good, but TI will not let me log in to my Acronis account. Error message "Connection to synchronization server failed". Check your internet connection or try again later" ("Verbindung zum Synchronisierungsserver fehlgeschlagen. Überprüfen Sie die Internetverbindung oder versuchen Sie es später.")

What I tried already:
- Of course, trying again later (for some days now)
- Shut of temporary my firewall and virus scan
- Checked login email address and password (if I enter a wrong password I get a different error message => hence, it seems to *have* a connection to the sync server to at least check my login credentials.
- De-installation and fresh installation of TI 2015

As a result of this huzzle TI tells me that I exceeded the amount of activations, but I can't resolve this as it is not connecting to the sync server...

Any help highly appreciated!

Best regards,
Claus