Python custom functions not getting called in fission logs error 502 bad gateway

[Shahnawaz-1]

I have installed fission and created
1 .Package
2. Env
3. function hello world
4. tested and running fine

But
When i tried to run custom functions like finding a max number.

    if x > y:
        return x
    return  #y
def max_of_three( x, y, z ):
    return max_of_two( x, max_of_two( y, z ) )
print(max_of_three(3, 6, -5))  

it gives a error

Error querying logs: Internal error - 502 Bad @Gateway%

Also when i try to check logs the same error reflecting

@vishal-biyani
@sanketsudake
@fission
@fission.io