Apache 2.4 and SSL: AH02217: ssl_stapling_init_cert: can't retrieve issuer certificate

I was all the day searching in google and here, and nothing works to me.

I have a Ubuntu 16.04 server with Apache 2.4 with multiple virtual hosts. I am trying to configure a Self-Signed SSL Certificate for one of my sites. I follow this two tutorials:

https://www.digitalocean.com/community/tutorials/how-to-create-a-self-signed-ssl-certificate-for-apache-in-ubuntu-16-04

https://www.digitalocean.com/community/tutorials/how-to-set-up-multiple-ssl-certificates-on-one-ip-with-apache-on-ubuntu-12-04

But right know, if I try to enter my site, it's not visible. In Firefox, throw me a error like this:

Secure Connection FailedThe connection to the server was reset while the page was loading.    The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.    Please contact the website owners to inform them of this problem.

If I tail the /var/log/apache2/error.log after run service apache2 restart I find this errors:

[ssl:error] [pid 14916] AH02217: ssl_stapling_init_cert: can't retrieve issuer certificate! [subject: emailAddress=user@emial.com,CN=example.com,OU=Example,O=Example,L=Test,ST=Test,C=MX / issuer: emailAddress=user@emial.com,CN=example.com,OU=Example,O=Test,L=Test,ST=Test,C=MX / serial: 9AD648D7C9AD4A03 / notbefore: May  3 22:28:46 2017 GMT / notafter: May  3 22:28:46 2018 GMT][ssl:error] [pid 14916] AH02604: Unable to configure certificate example.com:443:0 for stapling

And I don´t understand what is wrong. My Virtual Hosts look like this:

<VirtualHost *:80>    DocumentRoot /var/inetpub/example.com    ServerName example.com    ServerAdmin user@email.com    ErrorLog "${APACHE_LOG_DIR}/example-error.log"    CustomLog "${APACHE_LOG_DIR}/example-access.log" common</VirtualHost><IfModule mod_ssl.c><VirtualHost *:443>        ServerAdmin user@email.com        ServerName example.com        DocumentRoot /var/inetpub/example.com        SSLEngine on        SSLCertificateFile /etc/apache2/ssl/example.com/apache-selfsigned.crt        SSLCertificateKeyFile /etc/apache2/ssl/dexample.com/apache-selfsigned.key<FilesMatch "\.(cgi|shtml|phtml|php)$">             SSLOptions +StdEnvVars</FilesMatch><Directory /usr/lib/cgi-bin>             SSLOptions +StdEnvVars</Directory>        BrowserMatch "MSIE [2-6]" \                      nokeepalive ssl-unclean-shutdown \                      downgrade-1.0 force-response-1.0</VirtualHost></IfModule><Directory /var/inetpub/example.com>        AuthType Basic        AuthName "Restricted Content"        AuthUserFile /etc/apache2/.htpasswd        Require valid-user        Options Indexes FollowSymLinks MultiViews        AllowOverride All        Order allow,deny        Allow from all#       Require all granted</Directory>

The files /etc/apache2/ssl/example.com/apache-selfsigned.crt and /etc/apache2/ssl/dexample.com/apache-selfsigned.key exists. I don´t understand what is the problem... What should I check?

Thanks.

EDIT 1:

In the virtualhost I added this line:

SSLUseStapling off

And the error no longer appears in error.log, but I still can´t enter the site with https in the browser. I don´t if this help, but if directly in the server I use enlinks:

elinks https://www.example.com

This load me the site correctly. But if I try to enter in my computer browser, I can´t see it. The url without https works fine in both.