the last couple of months my bonsai leaves have started falling . At the moment it is left only with almost none leaves. Even the ones that are still on the tree are dry and ready to fall. New leaves that are occasionally growing on the tree they immediately wilt. I used to have the tree next to an open window during the winter but since the leaves started falling I moved it in a warmer corner in the house. In addition, I stopped watering the tree very often and now I only water it once a week. However, nothing seemed to have changed. I don't know what else to do to help it recover, so I was wondering whether I need to do something that I haven't thought of, such as pruning the roots, repoting it, etc?
I have attached pictures of the bonsai to have a look at it as I don't know what type of bonsai it is.
Could you please offer me any suggestions?
Thank you very much,