Hello,
In short you're getting this problem because the solver is likely getting to a maximum number of iterations without having the ability to find the best or better result. This may or may not be true (as there is not necessarily better results out there).
What happens when you change scale = TRUE? I can think that is partially one of the problems here as I can't think all your features are of the same scale of measurement.
In addition to this, I suggest trying some of the points mentioned in this answer here: https://stats.stackexchange.com/questions/37669/libsvm-reaching-max-number-of-iterations-warning-and-cross-validation