Tighten any loose bulbs and ensure all bulbs are rated "dimmable”.
Check that the wires connecting the dimmer are firmly secured.
If flickering continues, it may be caused by irregular power surges and spikes of electric energy moving along power lines and building wiring.
Flickering more frequently occurs at lower dim levels. There are two ways to set the lowest possible dimming level which may help with flickering. If you have enabled smart features, you can use the Feit Electric app. Under Settings, adjust the minimum brightness until you do not see flickering. You can also set this low-dim point manually on the dimmer. Follow the instructions in the Installation Guide for more information.
You can also watch this video for installation information and troubleshooting tips.