Homematic CCU2 - Internet LED keeps blinking due to NTP timeserver connection problem

I know that the CCU2 does not receive updates anymore from eQ-3, but it still works reliably together with OpenHAB 3.

However, since a couple of weeks ago, the Internet-LED kept blinking constantly, and I could not figure out why, nor finding a fix for it.

Through googling I found out that this happens because the CCU2 could not contact the NTP time server (which makes sense, since the local time of the CCU2 started to be off more and more). From what I understood, for some reason the CCU2 could not contact the default time server ntp.homematic.com anymore. Replacing it with another one (de.pool.ntp.org works great for me) solves the problem.

As said, maybe this is known to everyone else, but it took me a while to find this out.

Update: While it does solve the problem of not being able to reach the NTP-server at all, it does not solve the problem of a blinking internet LED if the internet connection was gone temporarily. In that case, from what I understood, the CCU2 has to be restarted.