Balance Sheet out of balance

Summary

Balance Sheet is out of balance by $793.02. . .what could cuase this?

Content

Our Balance Sheet for the end of December 2018 is out of balance by $793.02.

How do I even start to figure out how/why?

My suspicion is an AP transaction, or a consolidating process, which should be the only December transactions we've created since the imbalance reared its ugly head.  The value suggests an AP transaction over a consolidating transaction.

November is still in balance.

January 2019 is out of balance, but by ($303.97).  (That's a cumulative difference of $1,096.99)