I have this problem since 2 hours, can´t print anything with any filament.
I read through this post and wanted to try to disable the filemnt entanglement sensor. I found this article that describes how the filament sensor works and then I realized I had lost the spring that pushes up the Filament hub when I disconnected my AMS. This results in the hub always being in the lower position indicating that there is a tanglement.
Maybe this helps someone.
Now I gotta find that spring. 
Spring found! Printer works perfectly again!
Thanks, Changing the “Filament Tangle Detection” worked for me as well!
Same, I have tried to extrude the filament and it will not work.
I’m having problems with both my A1 and A1 Mini. They will extrude fine when calibrating, but when it goes to print it will either click or put down a horrible, bubbly first layer. It will extrude just enough to not trigger a warning. I’m at a total loss. The nozzle on my A1 wiggles when it clicks.
That seems like an issue with a screw missing. That or the buckle isn’t in place to hold the extruder. Hope that helps-
There were some loose screws. I tightened them up on all of my A1s and now they’re printing perfectly.
I had the same thing happening. I took it all apart cleaned the filament sensor and I’m back in business!
Thanks for the advise !!
How did you aline the idler arm? Mine doing the exact thing your post detailed. And I too have done everything I can think of even tearing don’t the whole head and no clog
Im super late to the party here bust just incase anyone new comes in, after multiple deasemble/ reasembles and many hours online, just turning off tangle detection did the trick!