This seems to be a bug in Exim. There is a patch mentioned in the following thread that I have no idea if it should be already on the latest Hestia version or not:
Just to clarify. Hestia uses the Exim package provided by the distribution (Debian or Ubuntu) and the only supported version using Exim 4.96 (the SRS patch was included in 4.96-RC2) is Debian 12, other versions are using older releases so the patch shouldn’t be applied (it isn’t a security issue so I don’t think it was backported to older releases). Ubuntu 24.04 uses Exim 4.97 but it isn’t supported by Hestia yet.
I set up new VPS with Ubuntu 22.04 and HestiaCP quite often. And every time in the logs I see all the same error given in this thread a year ago.
Can anyone answer if this is a problem with HestiaCP or Exim4 itself?
The log /var/log/exim4/paniclog is full of thousands of entries.
None of the advice in this thread has helped. There is no solution.
Found this thread with the same error, but SRS_SECRET = ${readfile{/etc/exim4/srs.conf}} is already in the config.
I want to make it clear again. Exim4 is installed and configured by HestaiCP on a clean Ubuntu 22.04. No manual changes have been made to the configs. And the mail server is not working.
Maybe there is a possibility to connect an external repository to update Exim4 to the latest actual version? As it is done by the panel with mariadb and nginx?