i installed CUCM 12.5 And IM & Presence 12.5 and integrated them, i add external database (MS SQL) and i configured Message archiver Feature, when 2 online users chat together with cisco jabber 12.8 ,messages stored in database i defined, but i have some problems: 1. when online user send message to offline user, online user receive this message : "Your message could not be delivered. Instant Messaging Server is unavailable." and offline user after login don't receive that mesage. 2. when user connect from another device (exp. phone) cant see history chat of other device(Desktop) finally my main goal is that users have same chat history from all their devices, and their chat are not saved locally and i cant find out what is functionality of message archiver?
You are already saving your chat history, but you need a DB as you configured, or a compliance server. IM&P itself is not going to do that without an external storage.
As I already told you, that is NOT a feature of IM&P, the only possible way in which you could do that, is to enable persistent chat rooms, and then instead of having a regular 1:1 conversation, create a persistent chat room for every conversation you want to have.