The colors of the rainbow are 7 but in front of me I have a white rainbow. You can see that it’s not a halo or other atmospheric optical effect, it’s a rainbow, but it’s white. That idea that seems so simple is difficult for me to assimilate, because they had always explained to me how rainbows are formed and why colors are seen, and there in front of me I had one that did not comply with the rules. How is it possible? what happened to it?

This rarity is called a cloudbow or fogbow, and can be seen before sunset in the winter months.
In summary, the water droplets in the environment are smaller and more spherical than raindrops, and this makes it possible to form a rainbow in which the colors overlap again to give almost white. I was very surprised to learn that despite the low temperatures (-6º C) there were drops of water in the air.
Les Cowley in his OPOD explains it, as always in a clear and visual way, much better than I could, so I’ll leave you the links to find out more.

https://www.atoptics.co.uk/fz851.htm
https://www.atoptics.co.uk/opa_bows.htm
https://www.atoptics.co.uk/fz1137.htm