First and foremost, welcome to our Community! @kamil.lisek.38226 

Thank you for informing us about this issue. I will gladly help you further to resolve this! 

Have you already tried rebooting the router? If not, can you please do so, following these steps:

1. Disconnect the router and the Media Converter/ONT (the small white or black box) from the power.
2. Wait at least 10 seconds. Then connect the Media Converter/ONT to the power again and let it restart for 30 seconds. Then connect the router to the power again.
3. Wait until everything has started up completely.
4. Check whether the services are working again.

Please let me know if this works, I am here to help you further if needed!

Hello, thanks for the answer, yes I tried all of that on Monday. It repaired itself yesterday evening (after a 24-hour disruption). Now all LED lights are green again. Wish you nice day.