What is the term for fear of getting fired from one's job?

Official expressions are:

Employment insecurity:

relates to the subjective or objective risk of (involuntary) reduction of welfare coming from employment, most drastically from the loss of employment.

Or

Fear of Job Loss:

The fear of job loss refers to the felt threat, stress, and perceived powerlessness due to the possibility of leaving the current job and being not hired in the labor market. Fear as such generates anxiety and lowers the well-being of workers and even their dependents.

(link.springer.com)