Solar House Number Plaque, Address Signs for Houses, Bright Backlit LED Lights Can Illuminate The Entire Night

I have had this in use for two weeks. Worked well until a few days ago. Now doing a steady blink when the light comes on. What happened?

Is this waterproof? Doesn't say anywhere like other similar products.

How does this mount to the house?

Should it last longer than one year? bought it in march, 2021. stopped working in december 2021. changed the battery and it still doesn't work.