Failed print, curling on calibration Prusa Mk3S

Hi,

I am struggling to get any successful prints ( it was hit and miss before, now is 90% fail). I have attached the calibration square and you can see it curls a huge amount. I've also shown a print which fails on first layer. I have a Prusa Mk3S. I have tried two different PLAs and the same exact effect.

Any thoughts what might be causing the curling?

Thanks

You have zero of very low adhesion to the print bed. Try setting the print head closer to the bed about 0.1 mm or 3 thou (0.003") And / Or use a bed adhesive like a thin layer of PVA glue stick Elmer or Prit depending on which side of the pond you are.