Overview
When sending IncaMail messages via the Mail Gateway Interface (MGI) on domains hosted by Green, errors may occur. In these cases, the message is not successfully delivered and the sending process terminates with an error message.
This issue exclusively affects setups where IncaMail is used via MGI. The normal receipt of IncaMail messages is not affected.
Symptom and Cause
When attempting to send, the following error message appears:
535 5.3.2 Relaying denied, no client certificate
The problem is caused by a cipher suite incompatibility between the services of Green and IncaMail.
Green expects certain cipher suites and TLS parameters during connection setup that are currently not compatible with the security and certification requirements of the IncaMail MGI. As a result, the SMTP handshake is aborted before authentication or sending can take place.
Due to this technical incompatibility, Green is considered, until further notice, a non-supported provider for using IncaMail via MGI.
Impact
| Area | Status |
|---|---|
| Sending via MGI (SMTP over Green) | ❌ |
| Receiving IncaMail messages on Green mailboxes | ✅ |
| Sending via Webmail or IncaMail Web Interface | ✅ |
| Sending via domains not hosted by Green | ✅ |
Status
The situation has been analyzed and confirmed by IncaMail.
A technical exchange with Green has been initiated.
Until a compatible solution is implemented, Green is considered a non-supported email service provider for sending via MGI.
Note: This only affects MGI-based communication. Web access to IncaMail or receiving messages remains possible.
Workaround
Currently, no solution is available for sending via Green infrastructure. Until technical clarification with Green is completed, we recommend:
Send exclusively via the IncaMail Web Interface
https://app.incamail.comUse an alternative mail provider if MGI is mandatory