Tajima Embroidery Errors - frustrated with bobbin thread issue

We've been having issues with our embroidery machine where the color thread is not holding with the bobbin thread. It pumps a couple of stitches through unsuccessfully before stopping with error 291. Recently, when changing between colors, there was no trimming done to the previous color and ultimately, the machine has to be stopped between each color to trim. Perhaps these issues are connected, but this machine has had enough problems to think they are separate.

The machine has been recalibrated, restrung and had all needles replaced within the past 7 days and has been oiled and maintained regularly. We have big orders to fill and any help would be graciously accepted.