Auth token decryption failed

Nobody has claimed this yet.

Hello, I have problem that some authentication attempts to our passbolt fails:

```
File "...", line 82, in login
self._session.authenticate()
File "/usr/lib/python3.7/site-packages/requests_gpgauthlib/gpgauth_session.py", line 231, in authenticate
return self.is_authenticated_with_token
File "/usr/lib/python3.7/site-packages/requests_gpgauthlib/gpgauth_session.py", line 215, in is_authenticated_with_token
user_token_result=self.user_auth_token
File "/usr/lib/python3.7/site-packages/requests_gpgauthlib/gpgauth_session.py", line 201, in user_auth_token
raise GPGAuthStage1Exception("Auth token decryption failed: %s", user_auth_token.status)
requests_gpgauthlib.exceptions.GPGAuthStage1Exception: ('Auth token decryption failed: %s', 'decryption failed')
```

```
def login(self):
self._session = GPGAuthSession(gpg=self._gpg, server_url=self.server_url)
assert self._session.server_fingerprint == self.server_fingerprint

self._session._user_passphrase = self.passphrase
self._session.authenticate()
```

Interesting thing is that it is working for approx 70% of all attempts but sometimes it ends in this exception. Repeating the authetication after failure will successfully pass. Am I doing anything wrong? Is there way how to debug it? Thanks for any advice.

Start at requests_gpgauthlib/gpgauth_session.py, especially user_auth_token, is_authenticated_with_token, and authenticate, and reproduce the intermittent failure using the login snippet. Compare successful and failed authentication attempts around the reported “decryption failed” status; done means the cause is understood and authentication no longer fails intermittently.

Written by the indexing model from the issue text.