An auth token's expiration must be less than one year from its issued-at time.
The token has expired.
Token has an invalid format (failed a regular expression check).
onAuthTokenRequested threw an exception.
Any other error not captured by another constant.
Iterable has invalidated this token and it cannot be used.
The request to Iterable's API did not include a JWT authorization header.
onAuthTokenRequested returned a null JWT token.
Iterable could not decode the token's payload (iat, exp, email,
or userId).
Iterable could not validate the token's authenticity.
The token doesn't include an email or a userId. Or, one of these
values is included, but it references a user that isn't in the Iterable
project.
The reason for the failure of an authentication attempt.
This is generally related to JWT token validation.
FIXME: Android returns the string (EG:
'AUTH_TOKEN_EXPIRATION_INVALID'), but iOS returns the enum value (EG:0). These should be standardized so that they both return the same type on either platform.