80 is too hot for pla - the bottom layers will deform as they'll be too soft to support the weight of the rest of the model - also won't harden properly.
And yeah 240 is realistically too hot for pla.

It's usually better to slow the first layer down and add a little bit of 'smush' -z-axis to the print instead.
You also want to make sure that the print area cooling fans the off for the first layer and sometimes the first two layers.

After 6 years of constant experimentation - I have found 65c is the perfect temp for pla - on almost any build surface.