[Not Solved]Line renderer ugly lines, how to fix?

If I use the Line renderer, I got really ugly lines, pink and the lines looks like triangles. How can I fix this?? Here I have an screenshot from my settings(if the screenshot is not shown, it is cause the maximum attachments is 2). Screenshot
(sorry for bad English, I’m German)

With help of @Jessespike, now the line is not pink anymore and I can set a custom color.
But the question is not solved yet, the lines does still looks like triangles.

I just want a line like this

Make a material and put it on the line renderer. Use a transparent shader like “Particles/AlphaBlended”.