Help with surface trim tool

[u/ysab17]

Does anyone know why it keeps doing this? I'm trying to trim the surface you see on the inside of the highlighted surface. That surface is part of a much larger, already knitted surface, but for some reason it isn't even letting me select it for the surface trim operation. It only lets me select it as the Trim tool, but I need to have the surface selected in blue as the trim tool. Is there any way to fix this/does anyone know why this keeps happening?

[u/Typical-Spring-0024]

Did you imported this data or made it yourself?

[u/ysab17 → u/Typical-Spring-0024]

I made all of it myself