According to Cambridge dictionary:
/sɑːlv/means to find an answer to a problem.
/rɪˈzɑːlv/means to solve or end a problem or difficulty.
When you solve something, you find (and presumably implement) a solution to it. This means that you have dealt with it successfully, finding what was quite possibly the only way (or at most one of a few ways) to succeed.
The question has been solved; the correct answer is posted for all to see.
When you resolve something (a problem, an issue, a question), you deal with it conclusively. You have finished it, it is done, there is nothing left to concern yourself about. This is not to say, however, that your handling of the matter was ideal, nor even necessarily satisfactory; there are many possible ways that the thing could have been dealt with, you picked one and saw it through.
The issue has been resolved, although none of us is happy with the final outcome.