Blend Materials not working.

I’m not sure if this is the right category for this question, first time using this forum. So if it’s wrong, I apologize.

When I try to make Blend Materials, I get this “Select two or more material instances to perform this operation.” error. I tried using materials, material instances and surfaces imported straight from Quixel. I manually add the materials, doesn’t work. I select the materials from the content browser, doesn’t work either. What am I doing wrong?

I am having same issue. i also have migrated my whole project in new file but same error occur (An error ocurred while creating Blend material.)

Same problem sept 23. Absolutely no way to make this work. HEEELP!!!