List Index out of range

Question

I am trying to remove an element from a list, if the element appears more than 1 time in the list. But when I start my programm, I get an error: list index out of range. Can somebody please tell me, why I am getting this error?

My code:

zahlen=[1,2,5,2,2,6]

a=len(zahlen)

for i in range(a):

element=zahlen[i]

aE=zahlen.count(element)

if aE>1:

zahlen.remove(element)

else:

continue

print(zahlen)