eufy 11s just beeps once continuously, red light is solid, what does that mean?

Solid red light with one continuous beep indicates the left or right main drive wheel is stuck.

Action required:

1. Immediately turn off the main power switch on the bottom of the RoboVac.
2. Turn the unit over and inspect both main wheels (the larger ones, not the small front swivel wheel).
3. Remove any hair, string, or debris wound tightly around the axles of either wheel. You may need to pull the wheels gently outward to access the axles.
4. Clear any obstruction from the wheel cavities.
5. Turn the power switch back on.

If that didn't work: If the beeping persists, a full restart may be needed. Turn the power off, wait two seconds, and turn it on again. Also check the smaller front swivel wheel for entanglement; clean it by pulling it out, removing debris, and clicking it back in.

Note: This error is distinct from other beep codes. Two beeps (solid red) is a side brush stuck. Three beeps (solid red) is a suction fan blockage. Four beeps (solid red) is a rolling brush jam.