"Timed out connecting to Loki"

I followed this tutorial https://grafana.com/blog/2021/07/19/iot-at-your-home-work-or-data-center-with-prometheus-metrics-and-grafana-cloud/ to get the ESP32 running. After I fixed the problem with the wrong certificate #10 the ESP was finnaly able to connect successfully but is getting always a timeout:

1675064609430 Begin serialization: Free Heap: 240572 Bytes used for serialization: 148 After serialization: Free Heap: 240572 After Compression Init: Free Heap: 240044 Required buffer size for compression: 204 Compressed Len: 132 After Compression: Free Heap: 240572 Sending To Prometheus Connecting... Connected. Sent, waiting for response Timed out connecting to Loki 1675064628071

I kicked out everything out related to the sensors and just tried to write the system time to the Grafan cloud. Things that I already tried:

Generate different API tokens with different roles (admin, metricsPublisher,...)
Change the timeout values in the library.
3 different WiFi networks did not change anything.
Tried Loki and Prometheus logins/API keys

Any suggestion or deeper debugging information would be higly apreciated. I don' t get the point what is going wrong.

grafana / prometheus-arduino

"Timed out connecting to Loki" #13