Here's why:
* "Malo" could be a misspelling of "malo" (bad/evil) in Spanish or Portuguese, but it doesn't make sense grammatically with "sole."
* "Sole" is usually a noun meaning the bottom of the foot or a type of fish. It doesn't make sense as a verb or adjective in this context.
If you can provide more context or the full sentence where you encountered this phrase, I might be able to help you understand its meaning.