I could not get the rgb led to work and did dig in a little deeper.
I found out ( i am not a real electronic expert) that there are several different types of 5050 rgb led with different type marking where some use the triangle as anode and some as cathode so because the rgb led did not function i tried so supply power the other way around on the led and you can allready guess now it works.
So it looks like the maker mixed up the types and did put the rgb led the wrong way.
So beware that this can be the case