The red light indicator on the docking station is always one of two issues.

1) The replaceable bag within the vacuum is either full or out of position.  Please replace the full bag or pull the bag out of the sliding area and place back in.  This will turn the light from red to white again.

2) Some sort of item or debris is caught in the suction piping that leads from the vacuum into the replaceable bag.

Try these steps in order to fix the issue:

• Unplug the docking station.
• Remove the replaceable bag.
• Pick up the docking station and give it a good shake.  It is a sturdy unit and we want to make sure whatever is causing the problem gets dislodged, so don't be too shy.
• Tap the docking station against the floor. Try tapping the side against the floor as well.  
• If you have any sort of cleaning or utility brush that is bendable and able to push fully through the tubing area, this can help make sure the internal bend is cleared out fully. 
• Now we can put the dock back in place and plug back in.
• At this point, return the bag into the dock. Close the lid and the light on the charging dock will return to strobing white.  The strobing white means the bag is in the right place and it will continue strobing until the vacuum is put on the charging dock.  Once the vacuum is docked the light will turn solid white to indicate it is connected and charging.