Yes, in fact, there are several reasons that an insurance company may decline your request for coverage.
Life insurers are in business to make money, so they analyze the risk if insuring everyone who applies for a policy.
If the risk is too great for the insurer to insure you for life insurance, then they may turn you down for coverage.
Some of the more common reasons a person would be turned down for life insurance may include COPD, emphysema, cancer, DUIs, AIDS, obesity, or if you are over 85 years old.
However, if you have been turned down, you may still be able to purchase a guaranteed-issue life insurance policy if you meet the age requirements.
To learn more, read this article: Can I Be Turned Down for Life Insurance?