The most direct fix:
x = 0
sum = x
while (sum <= 10):
x = x + 2
print x
sum = x + 2
print ('Good bye!') # <-- lower case, unindented
A shorter solution:
for x in range(2, 12, 2): # start at 2, increment by 2, up to but not including 12
print x
print 'Good bye!'