Error message is too generic. When invalid HH:mm is given in the correct format, the error message suggests the wrong format is given. It would be better for the error message displayed to be more specific i.e. differentiate between wrong format and invalid inputs.

Error message is too generic. When invalid HH:mm is given in the correct format, the error message suggests the wrong format is given. It would be better for the error message displayed to be more specific i.e. differentiate between wrong format and invalid inputs.