Why is the server returning ‘421 Closing transmission channel, Service Unavailable’ errors after an upgrade to build 3509? These errors might appear in the SMTP log.
This is known issue with systems which do not have an active GMS Anti-Spam key applied to their system. To fix this two system variables have to be added.
- Go to the Mail->Security->Control section of the administration interface
- Enable the ‘Allow direct editing of system variables’ option and click update.
- Go to Support->System Variables
- Add the following variables if they do not already exist.
(Replacing ‘domain.dom’ with the domain installed in GMS)
- Now stop and restart all of the GMS services or reboot the server.
If this does not work please contact Gordano Support for further assistance. The issue does not affect later builds of GMS.
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