Could not unserialize key data (use .p8 file as private key file, use ES256 algorithm)

[chenhongws]

Such was the code:
APNS_AUTH_KEY = './APNsAuthKey_SP7C6832EZ.p8'
f = open(APNS_AUTH_KEY)
secret = f.read()
token = jwt.encode(
payload={
"iss": "8X2A38Q9VD",
"iat": time.time()
},
key= secret,
algorithm= 'ES256',
headers={
"alg": "ES256",
"kid": "SP7C6832EZ",
}
)

But it run with error：
Traceback (most recent call last):
File "Http2AuthToken.py", line 31, in
"kid": "SP7C6832EZ",
File "/usr/lib/python2.7/site-packages/jwt/api_jwt.py", line 56, in encode
json_payload, key, algorithm, headers, json_encoder
File "/usr/lib/python2.7/site-packages/jwt/api_jws.py", line 98, in encode
key = alg_obj.prepare_key(key)
File "/usr/lib/python2.7/site-packages/jwt/algorithms.py", line 226, in prepare_key
key = load_pem_private_key(key, password=None, backend=default_backend())
File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/primitives/serialization.py", line 20, in load_pem_private_key
return backend.load_pem_private_key(data, password)
File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/multibackend.py", line 303, in load_pem_private_key
return b.load_pem_private_key(data, password)
File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1048, in load_pem_private_key
password,
File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1217, in _load_key
self._handle_key_loading_error()
File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/openssl/backend.py", line 1289, in _handle_key_loading_error
raise ValueError("Could not unserialize key data.")
ValueError: Could not unserialize key data.

Is there somebody can explain?

[wayland]

Try updating your acme and boto libraries; I had a similar sort of error, and it worked for me.