"You no longer want to wear your green coat."
Translation:Tu ne veux plus porter ton manteau vert.
That's odd. The most recent report I found was "vous ne voulez plus porter vos manteau vert", which isn't correct because the possessive adjective should be singular, "votre manteau vert". I don't know if that is your sentence or not, but if in the future you type vous ne voulez plus porter votre manteau vert and it is marked as incorrect, could you please get a screenshot? It could be a bug.
Use "plus" when the meaning is "no longer" or "not anymore". This indicates that at a past time you wanted to wear it, but now no longer do. Use "pas" when you simply mean "don't".
Je n'ai pas de thé. / I don't have tea.
Je n'ai plus de thé. / I no longer have tea. or I don't have anymore tea. (but I did at one point)