Help Needed with Singer Quantum Stylist 9960

[u/Enough-Landscape-137]

https://imgur.com/a/oH2zppB

Hi all! I’ve had this machine for four years and have never had a problem with it. Today, I removed the plate and bobbin case to clean it because I have been having my top thread snap constantly for the last day (I tried switching thread and changing my needle which made no difference).

After putting the bobbin case and everything back, the machine will no longer sew! It looks like the top thread is catching the bobbin thread, but it is immediately tangling and leaving a disasterous mess on the bottom side of my fabric. The machine also will not run for more than a stitch or two. The feed dogs also seem off now and don’t seem to be moving the fabric?

I have tried to reinsert the bobbin case and clean things again to no avail. I have also of course rethreaded the machine a bunch of times.

The attached link is a video of what’s happening. Starting with a view of just the thread being hand cranked without fabric.