There are several things that could cause the machine not to pick up the bobbin thread.

1. The upper thread could be tangled. Remove the thread completely from the machine.
2. The correct size spool cap should be used for the size of the thread spool. Re-thread the machine according to the directions in the manual.
3. Remove the bobbin and make sure the bobbin is threaded correctly in the shuttle race.
4. Remove any loose threads or lint in the shuttle race.
5. You could be holding the needle thread too tight. Hold the thread lightly to keep the end from going down into the shuttle.
6. The needle could be thread incorrectly. Thread the needle's eye from the front to the back.
7. The needle could be bent or incorrectly inserted. Install a new needle with the flat side of the needle facing the back.
8. The thread twist is either too tight or too loose. Incorrect twisting results in irregular loop formation. Try using a new spool.