Linear Advance not Working, M900 not Recognized (4 replies)

Hello there. I'm new in this forum and don't know if my issue is a bug, so I'm posting here.

Basically, after recently configuring and updating my printer to Marlin 2.0.7.2, I tried enabling the Linear Advance feature. At first, there would be the following compile error if #define LIN_ADVANCE was uncommented.
[attachment 117645 CompilerErrorScreenshot.png]
I therefore downloaded Marlin 2.0.7.2 with bug fixes (bugfix- 2.0.x) on the 06/02/2021, and replaced the generic Configuration.h and Configuration_adv.h files with the ones I had previously edited (also attached to this post). The code then compiled (with no errors this time) and uploaded. I started printing the Marlin K-factor calibration Pattern, but while printing the 3D printer kept sending an error saying it did not recognize the command M900 (The one used to set the K-factor), and by the end of the print all the calibration lines looked the same, despite I have #define LIN_ADVANCE uncommented/enabled.

In Short:
- LIN_ADVANCE is enabled but M900 is not recognized while printing. I am using Marlin 2.0.7.0 bugfix.

I hope I made myself clear and that someone can help me to solve this. :)
Thank you