ISP (Telekom Germany) is blocking Zoom?

hi, 

I've since ~2 weeks the issue that my router (speedport smart 3) firewall (which can't be deactivated) is blocking the IPs from Oracle cloud which is used for zoom calls. 

In the logs I can see that entry: 
Firewall event: An event [UDP SYN FLOOD IP] : was detected. Address 193.122.*.* : 8801 was identified as the sender. The recipient was identified as 84.173.*.* : 63827.

* were added by me to hide the full ip adress. 

Telekom is not aware of any issues and asked me to reach out to zoom if they are any settings which might create these issue.