[CentOS] rsync: did not see server greeting.

Wed Oct 23 09:04:05 UTC 2019
Ralf Prengel <ralf.prengel at rprengel.de>

Hallo,
until last week I used a debian system for syncing debian and centos  
mirrors. Everything worked fine for years.
After installing centos 7 rsync doesn t work any longer. The  
configuration of the firewall is the same as before.

The message  I see is
rsync: did not see server greeting.

Has anyone a hint for me?
Are ther any main differences between rsync debian and rsync centos?

Thanks
Ralf