SSLV3_ALERT_HANDSHAKE_FAILURE

[ILPlais]

Bug Report

• I have checked that there is no existing issue dealing with this problem.

Summary

I'm trying to add my IMAP account. My server uses TLS on port 993.

Eonvelope version

Version 0.7.1

Steps to reproduce *

1. On the page: /accounts/add/
2. Username: lionel.plais@[RETRACTED]
3. Server URL to: imapssl.[RETRACTED]
4. Protocol: IMAP4
5. Port: 993
6. Timeout: 10s

Bug behaviour

Testing this account data failed: A SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] ssl/tls alert handshake failure (_ssl.c:1081) occurred during connecting on account!

Logs *

eonvelope-web  | 2026-06-08T16:43:08.751716680Z {"asctime": "2026-06-08 16:43:08,751", "levelname": "INFO", "name": "core.models.Account", "module": "Account", "funcName": "test", "lineno": 321, "message": "Testing Compte lionel.plais@[RETRACTED] avec le protocole IMAP4_SSL ..."}
eonvelope-web  | 2026-06-08T16:43:08.828932040Z {"asctime": "2026-06-08 16:43:08,822", "levelname": "ERROR", "name": "core.utils.fetchers.IMAP4_SSL_Fetcher", "module": "IMAP4_SSL_Fetcher", "funcName": "connect_to_host", "lineno": 80, "message": "Error connecting to Compte lionel.plais@[RETRACTED] avec le protocole IMAP4_SSL!", "exc_info": "Traceback (most recent call last):\n  File \"/opt/src/core/utils/fetchers/IMAP4_SSL_Fetcher.py\", line 67, in connect_to_host\n    self._mail_client = imaplib.IMAP4_SSL(\n                        ~~~~~~~~~~~~~~~~~^\n        host=mail_host,\n        ^^^^^^^^^^^^^^^\n    ...<2 lines>...\n        ssl_context=ssl_context,\n        ^^^^^^^^^^^^^^^^^^^^^^^^\n    )\n    ^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 1641, in __init__\n    IMAP4.__init__(self, host, port, timeout)\n    ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 208, in __init__\n    self.open(host, port, timeout)\n    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 1654, in open\n    IMAP4.open(self, host, port, timeout)\n    ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 318, in open\n    self.sock = self._create_socket(timeout)\n                ~~~~~~~~~~~~~~~~~~~^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 1645, in _create_socket\n    return self.ssl_context.wrap_socket(sock,\n           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^\n                                        server_hostname=self.host)\n                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/ssl.py\", line 455, in wrap_socket\n    return self.sslsocket_class._create(\n           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^\n        sock=sock,\n        ^^^^^^^^^^\n    ...<5 lines>...\n        session=session\n        ^^^^^^^^^^^^^^^\n    )\n    ^\n  File \"/usr/local/lib/python3.14/ssl.py\", line 1076, in _create\n    self.do_handshake()\n    ~~~~~~~~~~~~~~~~~^^\n  File \"/usr/local/lib/python3.14/ssl.py\", line 1372, in do_handshake\n    self._sslobj.do_handshake()\n    ~~~~~~~~~~~~~~~~~~~~~~~~~^^\nssl.SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] ssl/tls alert handshake failure (_ssl.c:1081)"}
eonvelope-web  | 2026-06-08T16:43:08.839439051Z {"asctime": "2026-06-08 16:43:08,832", "levelname": "ERROR", "name": "core.models.Account", "module": "Account", "funcName": "get_fetcher", "lineno": 306, "message": "Failed to instantiate fetcher for Compte lionel.plais@[RETRACTED] avec le protocole IMAP4_SSL!", "exc_info": "Traceback (most recent call last):\n  File \"/opt/src/core/utils/fetchers/IMAP4_SSL_Fetcher.py\", line 67, in connect_to_host\n    self._mail_client = imaplib.IMAP4_SSL(\n                        ~~~~~~~~~~~~~~~~~^\n        host=mail_host,\n        ^^^^^^^^^^^^^^^\n    ...<2 lines>...\n        ssl_context=ssl_context,\n        ^^^^^^^^^^^^^^^^^^^^^^^^\n    )\n    ^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 1641, in __init__\n    IMAP4.__init__(self, host, port, timeout)\n    ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 208, in __init__\n    self.open(host, port, timeout)\n    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 1654, in open\n    IMAP4.open(self, host, port, timeout)\n    ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 318, in open\n    self.sock = self._create_socket(timeout)\n                ~~~~~~~~~~~~~~~~~~~^^^^^^^^^\n  File \"/usr/local/lib/python3.14/imaplib.py\", line 1645, in _create_socket\n    return self.ssl_context.wrap_socket(sock,\n           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^\n                                        server_hostname=self.host)\n                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/usr/local/lib/python3.14/ssl.py\", line 455, in wrap_socket\n    return self.sslsocket_class._create(\n           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^\n        sock=sock,\n        ^^^^^^^^^^\n    ...<5 lines>...\n        session=session\n        ^^^^^^^^^^^^^^^\n    )\n    ^\n  File \"/usr/local/lib/python3.14/ssl.py\", line 1076, in _create\n    self.do_handshake()\n    ~~~~~~~~~~~~~~~~~^^\n  File \"/usr/local/lib/python3.14/ssl.py\", line 1372, in do_handshake\n    self._sslobj.do_handshake()\n    ~~~~~~~~~~~~~~~~~~~~~~~~~^^\nssl.SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] ssl/tls alert handshake failure (_ssl.c:1081)\n\nThe above exception was the direct cause of the following exception:\n\nTraceback (most recent call last):\n  File \"/opt/src/core/models/Account.py\", line 304, in get_fetcher\n    fetcher = self.get_fetcher_class()(self)\n  File \"/opt/src/core/utils/fetchers/IMAP4Fetcher.py\", line 104, in __init__\n    self.connect_to_host()\n    ~~~~~~~~~~~~~~~~~~~~^^\n  File \"/opt/src/core/utils/fetchers/IMAP4_SSL_Fetcher.py\", line 81, in connect_to_host\n    raise MailAccountError(error, _(\"connecting\")) from error\ncore.utils.fetchers.exceptions.MailAccountError: A SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] ssl/tls alert handshake failure (_ssl.c:1081) occurred during connecting on account!"}
eonvelope-web  | 2026-06-08T16:43:08.844529373Z {"asctime": "2026-06-08 16:43:08,844", "levelname": "INFO", "name": "core.mixins.HealthModelMixin", "module": "HealthModelMixin", "funcName": "set_unhealthy", "lineno": 70, "message": "Setting Compte lionel.plais@[RETRACTED] avec le protocole IMAP4_SSL to unhealthy because of error: A SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] ssl/tls alert handshake failure (_ssl.c:1081) occurred during connecting on account!"}
eonvelope-web  | 2026-06-08T16:43:08.844951510Z {"asctime": "2026-06-08 16:43:08,844", "levelname": "INFO", "name": "core.models.Account", "module": "Account", "funcName": "test", "lineno": 326, "message": "Testing Compte lionel.plais@[RETRACTED] avec le protocole IMAP4_SSL failed with error: A SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] ssl/tls alert handshake failure (_ssl.c:1081) occurred during connecting on account!."}
eonvelope-web  | 2026-06-08T16:43:08.845430463Z {"asctime": "2026-06-08 16:43:08,845", "levelname": "INFO", "name": "core.mixins.HealthModelMixin", "module": "HealthModelMixin", "funcName": "set_unhealthy", "lineno": 70, "message": "Setting Compte lionel.plais@[RETRACTED] avec le protocole IMAP4_SSL to unhealthy because of error: A SSLError: [SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] ssl/tls alert handshake failure (_ssl.c:1081) occurred during connecting on account!"}

Possible diagnosis

Errors in the TLS layer.

Fix it yourself?

I'm not that good! 😅

[Dacid99]

Hey thanks for getting in touch!

This looks like the SSL cert of the mailserver is self-signed or something similar.
Have you tried to use the 'allow unverified connection' option when setting up the account in Eonvelope? If it isn't shown you may need to allow its usage it in the admin settings first (https://eonvelope.readthedocs.io/latest/rst/configuration.html#admin-user-settings).

[ILPlais]

I keep getting the same error. Yet the server has a valid TLSv1.2 certificate. I have no connection issues with Thunderbird.

[Dacid99]

Ok then next please try to use the IMAP (insecure) protocol. It doesn't use TLS at all.

[ILPlais]

The connection works without the TLS encryption layer. But the point isn't to send my password in plain text over the network 😅

[Dacid99]

Yup I agree, that's not a good idea 😅
But it's good to see that at least some connection could be established.

I'll take a deeper dive into the code to see where the problem lies.

[ILPlais]

I tried using a test account on the same server, and the connection works fine with IMAP without encryption.