AutoSSL HTTP validation fails with 404 when using ea-tomcat85/ProxyPass

Symptoms

AutoSSL fails to process a domain with a 404 error:

CONFIG_TEXT: Local HTTP DCV error (domain.tld): The system queried for a temporary file at “http://domain.tld/.well-known/acme-challenge/-ZK6SR0LH2PRT2S87GUDRW2K9PJIOFRV”, but the web server responded with the following error: 404 (404). A DNS (Domain Name System) or web server misconfiguration may exist.

Cause

A proxy is redirecting all content for the domain, which causes the AutoSSL HTTP validation to fail.

Resolution

Add an exclude for the AutoSSL validation directory to the server's proxy configurations:

CONFIG_TEXT: ProxyPass /.well-known/ !

Additional Resources

Where should I add customizations to Apache?