I started MESSAGE+ on a 2nd MAC AIR that I have.  When I went back to the first one I saw a message saying" This device has been disconnected from the Integrated Messaging service. Do you wish to browse your messages offline or erase all messages from the device and reconnect?"  and the only response is ERASE & RECONNECT.   What does that mean?  I can't get out of it.  Can I run on two machines at same time?