The Enphase monitoring system will sometimes show an error that the microinverters are not reporting. This is not the same as "solar not producing power" - monitoring and production are two separate functions - but it's a good idea to fix this ASAP to make sure you have good data about your system health.
Here is a guide on the Enphase website: How to fix Microinverters Not Reporting
More Enphase support guides: Enphase Support
If you've tried some basic troubleshooting, feel free to reach out to our support team and we'll help fix this error.