Why does my Goodman a/c blower motor randomly not work?

Motor controller and or run start capacitor (s) are going bad. That's my first guess. It works when cold(not used for a while) then once used it gets hot ad does not work.

I think we are out of DIY territory if the problem is in the ac side of the system, With the limited info provided I would be looking at a low pressure safety switch on the compressor. There are both low pressure and high pressure switches to protect the system, as the temperature drops the Freon vapor pressure drops, if the pressure is below the set point this keeps the compressor from damage and the condenser should not be used with a gas furnace so it may be a problem with the controls are there any lights on the control board. What is the model #. Since it only fails after dark . almost all condensers have a contactor or relay and a start / run capacitor but as it is failing after dark I would look at Freon pressure for the AC but only a control board / programible thermostat explains the gas system not working, I would check the thermostat first and to have the Freon pressure checked you do need a licensed hvac tech.