What does the error Unable to get interface configuration: 22 Invalid argument mean?

This is an error that occurs when Exim is trying to find out the all the IP addresses on all of the local host's interfaces. If you have lots of virtual interfaces, this can occur if there are more than around 250 of them. The solution is to set the option local_interfaces to list just those IP addresses that you want to use for making and receiving SMTP connections.

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