messenger

i find every time i open messenger on my macbook pro, I am offline. I have to sign in every time. After I sign in, I attempt to go into my account to save my password. I am asked to type in my Apple ID password and do so with no problems. Then when I select "details" I get another pop up window that shows my Apple ID email address and in the two password boxes, bullets which should spell out my ID but when I do over write to up date it and save it, It always defaults back to the old apple ID password I had. I just tried to insert screenshots but for some reason it is not working for me at the moment. hmm. anyways, I hope someone can give me some direction /help on what my problem is.