FFF Printer Hardware Troubleshooting Guide
First layer is either too "squished" or does not stick to the bed
This problem could occur for a variety of reasons.
A clean bed plate
Our fingers have oils. Even a small amount of fingerprint oil can prevent filament from sticking to the bed. To remove oils, wipe the bed with a cloth moistened with Isopropyl Alcohol, and ensure that the surface is dry before printing.
Accounting for Thermal Expansion
For printers with a thick metal bed plate, thermal expansion may play a role in this issue. As metal beds heat up, they expand.