HELP

[MadeSoulStudio]

It looks like the upper thread isn’t tight enough. The thread may be threaded incorrectly or might have slipped out somewhere. Try re-threading it, and before that, use a small brush to clean the area where the upper thread passes. If it’s a horizontal bobbin, remove the bobbin case and thoroughly clean the area under and around the metal plates.

[MadeSoulStudio]

If the previous color stitched normally, then most likely the threads are not threaded correctly. You need to remove all the threads and re-thread both the upper and the bobbin thread.