If your S1 Pro triggers an "E77" error, please try the following troubleshooting steps:

1. Remove the robot from the base station and use an alcohol wipe to clean the charging pins on the robot and the base station.

2. Press the charging pins on the base station to check if they extend and retract properly. This method can verify that the charging pins are not stuck.

3. Inspect the clean water outlet to confirm it is not damaged.

4. Inspect the connection between the robot and the base station's charging pins.

If you have any other questions regarding the S1 Pro, please don't hesitate to contact us for further assistance.