hello. new to the 3d printing game here. I purchased an anycubic i3 mega about three months ago. I have printed several designs without any issues. today my printer is not printing. when I press print it sets up to print then travels and lays out one bead of filament and when layering the second bead it stops in the middle of the bead and just puts a blob of filament there and just stays at that point. any ideas as to what is causing this. please help.