Make sure the module is turned ON while charging! Otherwise the battery cannot be charged.
Try changing the charging adapter you are using.
If you are charging via a USB port on your computer or laptop, switch to a different port. Some ports may be in stand-by mode and do not supply enough power.
Make sure you are using the original cable. If this does not work, try using another cable.
See more about charging in the Preflight section.
To understand all LED blinking patterns, look here.