composer error on installation contao 4.4.48

[robvis]

Hi,
I installed SyncCto in my DEV environment, all well.
Now I'm trying to install in my TEST environment, but I get a composer error "The background task has stopped unexpectedly. Please check the console protocol".
I cleaned composer cache, no success.
Installing other extensions (e.g. LEADS from Terminal42) gives no issues.
Do you have any idead what could be wrong.
Contao 4.4.48
PHP 7.2.20

[Manfred-Gipp]

install first ctocommunication and synccto. After that, you can install all other extensions