403 error when verifying domain for SSL certificate?

Question

Digital certificates

I ran the check according to the instructions on doc.ispsystem.ru NOT through DNS. As a result, error 403:

There is such a topic on the ISP forum forum.ispsystem.ru/showthread.php?31832-ISPmanager... but there the problem is solved by changing .htaccess, I have a bare site, it does not have any .htaccess and delete or nothing to change. What to do in this case?
Errors in apache log:
There are a couple of errors:
[Sat Jun 09 14:38:03.954939 2018] [mpm_prefork:notice] [pid 28264] AH00169: caught SIGTERM, shutting down
But mostly these 4 errors are repeated:
[Sun Jun 10 15: 56:43.898619 2018] [mpm_prefork:notice] [pid 26838] AH00171: Graceful restart requested, doing restart
[Sun Jun 10 15:56:43.961376 2018] [alias:warn] [pid 26838] AH00671: The Alias ​​directive in /etc/apache2/conf.d/letsencrypt.conf at line 1 will probably never match because it overlaps an earlier Alias.
[Sun Jun 10 15:56:43.989735 2018] [mpm_prefork:notice] [pid 26838] AH00163: Apache/2.4.18 (Ubuntu) mpm-itk/2.4.7-04 OpenSSL/1.0.2g configured -- resuming normal operations
[Sun Jun 10 15:56:43.989754 2018] [core:notice] [pid 26838] AH00094: Command line: '/usr/sbin/apache2'