Sometimes it works, most requests are error "Process exited before completing request"

[oopsodd]

Here is my log outputs:
Duration: 671.75 ms Billed Duration: 700 ms Memory Size: 1536 MB Max Memory Used: 452 MB
Process exited before completing request

Other times I got this error:
cannot identify image file: IOError
Traceback (most recent call last):
File "/var/task/lambda_function.py", line 122, in lambda_handler
labels = predict(url, mod, synsets)
File "/var/task/lambda_function.py", line 66, in predict
img = Image.open(img_file.name)
File "/var/task/PIL/Image.py", line 1916, in open
raise IOError("cannot identify image file")
IOError: cannot identify image file

Other times I got this:
module initialization error: [Errno 28] No space left on device

Sometime it works perfectly a few minutes.