Gap in application metrics

We noticed there were some gaps in Fly.io Grafana metrics from 1/16/2023 15pm until 1/17/2023 15pm for one of our apps.
On the other side we do see traces in our Honeycomb coming in from that period, so that probably means that our application did work, but the prometheus data is missing.
Could you help me understand what is going on? What else can I check to confirm this? What could be the reason behind this?