I can no longer access ispconfig after Certbot installation

And examine mysql logs to see why mysql is not starting.

 

this is what I got with your suggestion:

Code:

*** System restart required ***
You have new mail.
Last login: Wed Jan 15 11:00:51 2020 from 95.246.119.141
root@webitalia:~# less /var/log/apache2/error.log
[Wed Jan 15 06:25:04.898534 2020] [:error] [pid 4875] python_init: Python version mismatch, expected '2.7.6', found '2.7.15+'.
[Wed Jan 15 06:25:04.900693 2020] [:error] [pid 4875] python_init: Python executable found '/usr/bin/python'.
[Wed Jan 15 06:25:04.900729 2020] [:error] [pid 4875] python_init: Python path being used '/usr/lib/python2.7:/usr/lib/python2.7/plat-x86_64-linux-gnu:/usr/lib/python2.7/lib-tk:/usr/lib/python2.7/lib-old:/usr/lib/python2.7/lib-dynload'.
[Wed Jan 15 06:25:04.900769 2020] [:notice] [pid 4875] mod_python: Creating 8 session mutexes based on 150 max processes and 0 max threads.
[Wed Jan 15 06:25:04.900786 2020] [:notice] [pid 4875] mod_python: using mutex_directory /tmp
[Wed Jan 15 06:25:05.036760 2020] [ssl:warn] [pid 4875] AH01906: webitalia.it:8080:0 server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Wed Jan 15 06:25:05.037174 2020] [ssl:error] [pid 4875] AH02217: ssl_stapling_init_cert: can't retrieve issuer certificate! [subject: CN=webitalia.it,OU=webitalia,O=webitalia,L=reggio calabria,ST=italia,C=IT / issuer: CN=webitalia.it,OU=webitalia,O=webitalia,L=reggio calabria,ST=italia,C=IT / serial: 439F74C556910DC86E761E55C2343F0ADD0B31F6 / notbefore: Jun 24 22:08:20 2019 GMT / notafter: Jun 21 22:08:20 2029 GMT]
[Wed Jan 15 06:25:05.037195 2020] [ssl:error] [pid 4875] AH02604: Unable to configure certificate webitalia.it:8080:0 for stapling
[Wed Jan 15 06:25:05.037593 2020] [mpm_prefork:notice] [pid 4875] AH00163: Apache/2.4.29 (Ubuntu) mod_fcgid/2.3.9 mod_python/3.3.1 Python/2.7.15+ OpenSSL/1.1.1 /var/log/apache2/error.log

 

That is the timestamp from log. Is the problem happening at that time? If not, look at the log entries at the time the problem appears.
Those lines you posted in #22 look like there is problem with the certificate. But you began this thread with problem after certbot installation, so that is to be expected.
You do not seem to know how to examine the log files on your host. It is possible to pay for support to get your system fixed, see https://www.ispconfig.org/support/