Warning appears when adding custom Exim routers with valid redirect_router entries

Symptoms

When using the Advanced Editor in Exim Configuration Manager to add a redirect_router entry with a valid router name, a warning similar to the following is displayed.

Warning! directive_matcher could not parse error: 2021-05-05 13:28:20 cwd=/usr/local/cpanel/whostmgr/docroot 4 args: /usr/sbin/exim -bV -C /etc/exim.conf.test.work.6f9e3861
2021-05-05 13:28:20 Exim configuration error:
  new_router "fail_remote_domains" not found for "redirect_all" router

Description 

The warning displayed indicates that the named router doesn't exist, even though the router does exist, such as when using a router defined in the default Exim configuration. Ignoring the warning allows the configuration to be saved, and Exim restarts without issue. Exim will process email as intended since the router does exist and the configuration is valid.

We have opened an internal case for our development team to investigate this further. For reference, the case number is CPANEL-40192. Follow this article to receive an email notification when a solution is published in the product.

Workaround

Ignore the warning.