If the main lights flash when the door is closing and the door reverses to the open position it is a sensor problem. Check the sensors very closely for the slightest flicker. Tweak them just a bit. This is almost always the reason for an intermittent problem. This is also a problem that can occur only when the door is closing. If the door stops on the way up increase the 'up force'. You will find this control on the rear of the opener. Do not increase the 'down force'.

Thanks for the follow-up Don. For more information, the main lights don't always flash when the door stops. It never reverses course when it freezes. It just stops and doesn't go any further.

If I increase the 'up force', what would be the cause for the door to freeze when closing? Could all of this be occurring due to the door springs being out of balance?

I think you hit the nail. It sure sounds like your door is out of balance or has hardware problems.