Can't send mail using apache commons mail when smtp appender for log4j is configured

Question

I have a working code that creates and sends an org.​apache.​commons.​mail.HtmlEmail (version 1.5), but that same code doesn't word when I have SMTPAppender configured for log4j2 (version 2.1), if I remove the SMTPAppender, my code runs again. This is the log from when SMTPAppender is configured and my code fails:

Loading javamail.default.providers from jar:file:/home/stirr/.m2/repository/com/sun/mail/javax.mail/1.5.6/javax.mail-1.5.6.jar!/META-INF/javamail.default.providers
DEBUG: loading new provider protocol=imap, className=com.sun.mail.imap.IMAPStore, vendor=Oracle, version=null
DEBUG: loading new provider protocol=imaps, className=com.sun.mail.imap.IMAPSSLStore, vendor=Oracle, version=null
DEBUG: loading new provider protocol=smtp, className=com.sun.mail.smtp.SMTPTransport, vendor=Oracle, version=null
DEBUG: loading new provider protocol=smtps, className=com.sun.mail.smtp.SMTPSSLTransport, vendor=Oracle, version=null
DEBUG: loading new provider protocol=pop3, className=com.sun.mail.pop3.POP3Store, vendor=Oracle, version=null
DEBUG: loading new provider protocol=pop3s, className=com.sun.mail.pop3.POP3SSLStore, vendor=Oracle, version=null
DEBUG: getProvider() returning provider protocol=smtps; type=javax.mail.Provider$Type@240a1e4d; class=com.sun.mail.smtp.SMTPSSLTransport; vendor=Oracle
DEBUG SMTP: useEhlo true, useAuth false
DEBUG SMTP: trying to connect to host "localhost", port 465, isSSL true
mai. 09, 2022 10:36:01 AM nfce.receita.nfe.envio.SendEmail sendXMLsAndReports
SEVERE: null
org.apache.commons.mail.EmailException: Sending the email to the following server failed : smtp.gmail.com:465

Pay attention where it says:

"trying to connect to host "localhost", port 465, isSSL true"

When I remove SMTPAppender, this message change and try to connecto to the correct host:

"trying to connect to host "smtp.gmail.com", port 465, isSSL false"

EDIT 1:

This is the relevant part of my log4j2.xml and the class that sends my email:

<Configuration status="INFO">
    <Appenders>
        <SMTP name="Mail" subject="My Subject" 
              to="[email protected]" 
              from="[email protected]"
              smtpUsername="[email protected]" smtpPassword="mypasswd"
              smtpHost="smtp.gmail.com" smtpPort="465" bufferSize="50"
              smtpProtocol="smtps" smtpDebug="true">
        </SMTP>
        
        <Async name="Async">
            <AppenderRef ref="Mail"/>
        </Async>
    </Appenders>
    
    <Loggers>    
        <Root level="info">
            <AppenderRef ref="Async"/>
        </Root>
    </Loggers>
</Configuration>

ps: I omitted console appender and file appender to focus on smtp appender configuration

org.apache.commons.mail.HtmlEmail email = new HtmlEmail();
email.setHostName("smtp.gmail.com"); 
email.setAuthentication("[email protected]", "mypasswd");
email.setSmtpPort(465);
email.setSSLOnConnect(true);
email.setStartTLSEnabled(true);
email.setFrom("[email protected]", "ERROR SISEMAIL");
email.addTo("[email protected]");
email.setSubject("My Subject");
email.setHtmlMsg("My message");
email.setCharset("UTF-8");
email.setDebug(true);

if (attachs != null) {
    for (File attach : attachs) {
         if (attach != null) {
            EmailAttachment attachment = new EmailAttachment();
            attachment.setPath(attach.getAbsolutePath());
            attachment.setName(attach.getName());
            attachment.setDisposition(EmailAttachment.ATTACHMENT);
            email.attach(attachment);
        }
    }
} 

email.send();

EDIT 2:

I have made a project that illustrate the error: https://github.com/lleandroo93/sof-q72173964

The problem seems to be related to one local lib that I have no control and is essential to the project (cannot be replaced or removed), please follow the steps described in the README of the project