Hamilton Beach is a manufacturer of home appliances, including many different models of kitchen toasters. When a toaster's bread levers don't stay down, the toaster will not heat up. Normally, this is an electricity-related issue.
Check to see if the toaster is plugged into an electrical outlet. Hamilton Beach toaster levers will not depress if the unit is not plugged in.
Make sure that there has not been a recent power outage in your home or that the power is not currently off. Again, with no power travelling to the the toaster, its lever will not stay down.
Plug a working appliance into the outlet and turn it on to test whether or not the electrical outlet is working.
Check for any food that may be jammed into the toaster slot. If there is, the toaster will automatically shut off. It is designed not to turn on again by preventing its lever from depressing and staying down. Always unplug your toaster when removing food that is stuck inside and only use wooden utensils to clean it out.