How to use SMTPUTF8 with Exim

Symptoms

Clients that are attempting to make use of SMTPUTF8 while your server does not have it enabled may see errors similar to the following in the /var/log/exim\_mainlog

CONFIG_TEXT: 2021-11-15 12:26:00.383 [3539516] SMTP syntax error in "MAIL FROM: sender@example.tld SMTPUTF8

" H=(hostname) [203.0.113.2]:55653 I=[203.0.113.2]:465 SMTPUTF8 used when not advertised

Cause

SMTPUTF8 is not currently enabled.

Procedure

1. Log in to WHM as the root user
2. Navigate to Home / Service Configuration / Exim Configuration Manager
3. Select the Mail Tab.
4. Find the option Hosts to which to advertise the SMTPUTF8 SMTP option
5. Add * to support SMTPUTF8 for all hosts.
6. Scroll to the bottom of the page and click the blue save button

Please review the Exim Documentation for the full information on these configurations:

Exim Documentation - Main Configuration