Do you use Google Cloud Nightscout?

[Navid200]

If yes, currently, you need to log into your FreeDNS account at least once every 6 months. Otherwise, it will become dormant. That will stop your Nightscout.

To fix it, you just need to log into your account.
This goes over the details: https://navid200.github.io/xDrip/docs/Nightscout/FreeDNS_Min_Login.html

We are working on automating this so that you won't need to log in twice a year.