Wont let me draw Line or 3pt arc?

Hello,
I am using Solidworks 2020 and im having trouble drawing a curved line.
So I have two points 30" apart... instead of a straight line between them, I want an arc with just a tiny deviation of 2mm at the center. (so the center point is 2mm off from the centerline).
But it's acting like thats too small of a curve. If I use the line tool or 3-point-arc, I can draw exactly what I want, but when I click to confirm... it just disappears!

I have gone to visual and performance settings and increased them to max, but no change.
Why does the line disappear when I click to confirm?
If I draw the exact same thing with a 10mm deviation, it works just fine.

ok I figured it out through trial and error.
The radius using other methods was over 12,000 which I guess it just didnt like.
Had to make a midway point between the ends and use the spline tool.