Water or condensation inside an outdoor camera washes out the image and can short the electronics. You have to solve both how it gets in and how it fails to get out.

• Check seals and cable entries: aged gaskets and cable entries without a waterproof gland are the leading causes. Replace the seal and treat the entry with both sealing compound and a proper gland.
• Mounting angle: with the lens level or pointing up, rain runs along the housing onto the glass. Tilt the lens 5 to 15 degrees down and form a drip loop in the cable.
• Junction boxes and enclosures: keep all connections inside a waterproof box with cable entries facing down. A desiccant pack inside, replaced periodically, helps.
• Never drill extra holes: additional holes in the body destroy the ingress protection and drop an IP66 rating to nothing.
• If water has already entered: power down, open and air-dry without hot air, inspect the board for corrosion, and only re-apply power once it is dry and the seals are replaced.

Put seal replacement on an annual maintenance plan, shortened to six months in coastal or high-humidity locations.