The I2P network is currently under a Denial-of-Service attack. This attack affects I2P and i2pd but in different ways and is having a serious effect on network health. Reachability of I2P sites is badly degraded.
If you are hosting a service inside I2P and it is hosted on a Floodfill router, you should consider multihoming the service on a Floodfill-disabled router to improve reachability. Other mitigations are being discussed but a long-term, backward-compatible solution is still being worked on.