Failed to issue a Let's Encrypt certificate when verified via DNS

Symptoms

A Let's Encrypt certificate cannot be issued using TXT record verification without errors in the control panel.

An error of the following format is registered in the log at  /usr/local/mgr5/var/letsencrypt.log:

proc EXTINFO Run 'dig +noall +answer +authority +additional +noidnout +norecurse @109.195.38.32 _acme-challenge.exmaple.com. TXT' pid 45436

Causes

The current values ​​of TXT records are not available from the server with the panel.

Solution

Add the Option LetsencryptDisableIterativeDig line to the panel configuration file at /usr/local/mgr5/etc/ispmgr.conf.