You say that you still have anger. How much anger do you have relative to the amount of anger you had prior to forgiving? Forgiveness does not necessarily expunge all anger. A key is this: Is the anger controlling you or are you now in control of the anger? If the latter is the case, then you very well may be forgiving. As the late Lewis Smedes said, forgiveness is an imperfect act for imperfect people. You need not have perfect forgiveness in order to have accomplished it to some degree.
Yet, let us presume that you are not forgiving even though you have tried. If you still are motivate to forgive, you can start at the beginning of the forgiveness process and persevere with regard to this one person. As a final point, if you are having difficulty forgiving Person A, you might try first forgiving someone else, Person B. I suggest this because, for example, some people have trouble forgiving a partner if the partner’s behavior reminds them of one of their own parent’s behavior. Forgiving the parent first then frees the forgiver to have more success with forgiving the partner.
For additional information, see: Learning to Forgive Others.