It could be a full charge, or a poor charging line.
Because the portable wifi is powered by the battery, the charging light will not light up when the charge is full.
In addition, if the charging line is not smooth, the electricity can not be charged normally, and the charging lamp will not be bright at this time.
If this is the case, check to see if the charging line is loose or damaged.
If the charging line is normal, but the charging light is still not on, it may be that the device is faulty, and it is necessary to contact the manufacturer in time to repair or replace the device.