@Bean
    public JavaMailSender mailSender() {
        JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
        mailSender.setDefaultEncoding("UTF-8");


        return mailSender;
    }

mail.port= 465
mail.host= smtp.gmail.com
mail.username= username
mail.password= password
emailTo = info@beingsmart.it
emailSubject = ALERT - ePark Server

mail.smtp.auth = true
mail.smtp.starttls.enable = true

mail.properties.mail.smtp.socketFactory.class=javax.net.ssl.SSLSocketFactory
mail.properties.mail.smtp.socketFactory.fallback = false

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.mail.javamail.JavaMailSender]: Factory method 'mailSender' threw exception; nested exception is java.lang.NoClassDefFoundError: javax/mail/AuthenticationFailedException
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
    ... 49 more
Caused by: java.lang.NoClassDefFoundError: javax/mail/AuthenticationFailedException
    at it.besmart.config.AppConfig.mailSender(AppConfig.java:128)
    at it.besmart.config.AppConfig$$EnhancerBySpringCGLIB$$b2a09c0.CGLIB$mailSender$7(<generated>)
    at it.besmart.config.AppConfig$$EnhancerBySpringCGLIB$$b2a09c0$$FastClassBySpringCGLIB$$dd65f050.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:318)
    at it.besmart.config.AppConfig$$EnhancerBySpringCGLIB$$b2a09c0.mailSender(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162)
    ... 50 more
Caused by: java.lang.ClassNotFoundException: javax.mail.AuthenticationFailedException
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1285)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
    ... 61 more

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-mail</artifactId>
</dependency>