| Enumerator | 
|---|
| UNAVAILABLE | No TLS provider is available.  | 
| MISC | Miscellaneous TLS error.  | 
| BAD_CERTIFICATE | The certificate presented could not be parsed or failed validation.  | 
| NOT_TLS | The TLS handshake failed because the peer does not seem to be a TLS server.  | 
| HANDSHAKE | The TLS handshake failed because the peer's certificate was not acceptable.  | 
| CERTIFICATE_REQUIRED | The TLS handshake failed because the server requested a client-side certificate, but none was provided.  See g_tls_connection_set_certificate().  | 
| ENDOFFILE | The TLS connection was closed without proper notice, which may indicate an attack.  See g_tls_connection_set_require_close_notify().  | 
| INAPPROPRIATE_FALLBACK | The TLS handshake failed because the client sent the fallback SCSV, indicating a protocol downgrade attack.  Since glibmm 2.60:
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