The error message Blackout occurred. Recover print? appears if the power goes off for a longer period of time during printing, and the hotend and heatbed cool down. Therefore, the printer will wait for you to safely resume the print.
There is not much troubleshooting to do, so here's a couple of things you should check before resuming or canceling the print.
Troubleshooting
- Make sure that all of the printed objects are still attached to the steel sheet plate.
- Follow the instructions on the LCD screen and resume the print.
- Stay with the printer for 10 minutes and make sure that the print continues without any problems.
- If you suspect that at least one of the printed objects is about to get loose, it is usually better to restart the print.