So landborder all the way to the country I just fabricated on(how can i fabricate if outside range anyways?!) yet the game says I don´t have diplomatic range even the they are just on my border?!

Dont know if this will fix your issue but I had something similar happen where I couldn't interact with a region touching mine, it was own by Phygria (spl?) and when I click on their core provinces across the Mediterranian, it let me fabricate, but not when clicking on the one next to me.