According to Vedic astrology there are various types of Doshas. When an affliction or Dosha is present in the birth chart, it indicates the sin caused by an individual in one of their births.
The person would experience difficulties depending on the severity of the affliction. Some afflictions also indicate unfinished businesses from the previous life. These afflictions are a forewarning for an individual not to repeat the same action in this life and accrue bad karma, rather repent for the past acts.
These afflictions, depending on the severity, affect various areas of life, health, wealth, relationship, fortune, and happiness.
If you have any of Navagraha Dosha as per your birth chart of horoscope - you can perform the remedial homam or Navagraha dosha shanti parihara homam to reduce the impact of dosha