I can't understand this error

Question

word = input()
l=list(word)
for i,li in enumerate (l):
if(l[i] != "a" & "e" & "i" & "o" & "u"):
print(li)

Answer 1

& is bitwise 'and'
The keyword for logical 'and' is "and"

Also "e", "i", "o" and "u" are Truthy values

To check if 'li' isn't a vocal you could do
if li not in "aeiou":
print(li)

Answer 2

the problem is in the use of & operator with strings.

you can use instead :

if l[i] not in "aeiou":
print(l[i])

Answer 3

This code that may help you more:

word = list(input( ))
for e in word:
if e not in "aeiou":
print(i)

Answer 4

it should be like:

if ( (l[i] != 'a') & (l[i] != 'b') & ... )