There should be no issues to ping 220.127.116.11, or any public IP/domain in your current configuration, as long as Fritzbox has internet access.
Could attach a troubleshoot file to your question to review device settings? Please, replicate the issue, then access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there. The logs in the file might provide more insight into the issue.
Attached files are private and visible only to Teltonika Moderators.