Not sure why the AMS is saying it’s disconnected but there are a whole bunch of filament present sensors between the feed tower and the extruder. I wonder if one or more are jammed. There is one in the hub on the back, 4 in the hub underneath the AMS and one in each feed tower plus the one in the extruder. I found that the one in the extruder can be jammed against the housing even without any bits of filament in there.
Ima toot my own horn and post a link to this thread. Scroll down for my posts, I shared a few links to the wiki that seem to be well liked. 
Maybe it can help.