I get error 503 after upgrading to http 2 - apache2

Question

After upgrading to http 2.0, I always get error 503. Can anyone help me solve the problem?
error.log:
[Mon Jul 19 11:03:26.351473 2021] [mpm_event:notice] [pid 9022:tid 140512076250176] AH00493: SIGUSR1 received. Doing graceful restart
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message
[Mon Jul 19 11:03:26.407467 2021] [mpm_event:notice] [pid 9022:tid 140512076250176] AH00489: Apache/2.4.41 (Ubuntu) mod_fcgid/2.3.9 OpenSSL/1.1.1f configured -- resuming normal operations
[Mon Jul 19 11:03:26.407479 2021] [core:notice] [pid 9022:tid 140512076250176] AH00094: Command line: '/usr/sbin/apache2'
In /etc/apache2/mods-enabled I see http2.conf (if I'm right)
Virtual Host via mod_macro:
<Macro VHost $dir $domain>
<VirtualHost *:443>
Protocols h2 http/1.1
SSLEngine on
SSLCertificateFile /etc/ssl/certs/my.crt
SSLCertificateKeyFile /etc/ssl/private/my.key
AccessFileName .htaccess
DocumentRoot $dir/$domain/httpdocs/
ErrorLog $dir/$domain/error.log
ServerName $domain
ServerAlias www.$domain
<Directory />
Options FollowSymLinks
AllowOverride All
Require all granted
</Directory>
<Directory $dir/$domain>
Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
allow from all
Require all granted
</Directory>
</VirtualHost>
</Macro>
Update: domain error.log
[Mon Jul 19 12:47:06.338104 2021] [proxy:error] [pid 18649:tid 140511882213120] (13)Permission denied: AH02454: FCGI: attempt to connect to Unix domain socket /run/php/php8.0-fpm.sock (*) failed
[Mon Jul 19 12:47:06.338133 2021] [proxy_fcgi:error] [pid 18649:tid 140511882213120] [client 127.0.0.1:51542] AH01079: failed to make connection to backend: httpd-UDS
[Mon Jul 19 12:47:06.519092 2021] [proxy:error] [pid 18649:tid 140511882213120] (13)Permission denied: AH02454: FCGI: attempt to connect to Unix domain socket /run/php/php8.0-fpm.sock (*) failed
[Mon Jul 19 12:47:06.519108 2021] [proxy_fcgi:error] [pid 18649:tid 140511882213120] [client 127.0.0.1:51542] AH01079: failed to make connection to backend: httpd-UDS, referer: https://s2019/
[Mon Jul 19 12:47:12.305094 2021] [ssl:warn] [pid 9022:tid 140512076250176] AH01906: s2019:443:0 server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Mon Jul 19 12:47:12.305103 2021] [ssl:warn] [pid 9022:tid 140512076250176] AH01909: s2019:443:0 server certificate does NOT include an ID which matches the server name
Thank you for any help!

Answer 1

I hope it will be useful if you encounter the same situation. All I needed to do:
Open /etc/php/<version>/fpm/pool.d and replace values
listen.owner = www-data
listen.group = www-data
with data in /etc/apache2/envvars
export APACHE_RUN_USER=someuser
export APACHE_RUN_GROUP=someuser
And the result will be:
listen.owner = someuser
listen.group = someuser
At the end you need to restart fpm sudo service php<version>-fpm start
By the way, php-fpm version may differ from your php version. For example, entering php -v shows me 7.4. But
<?php phpinfo();
now shows me 8.0. So I had to choose this dir /etc/php/8.0/fpm/pool.d