Try to check below steps to ensure Transaction is initiated properly

1. Make sure proper propagation level is configured for your @Transactional method, which by default is Propogation.REQUIRED

2. If method annotated with @Transactional is called within the same class, there is a chance the transaction doesn't get initiated, so you can move the method to separate Service class and check.

3. If there is any exception thrown in the code flow before to the method execution, then transaction might not be initiated