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Message could not be sent. Mailer Error: SMTP Error: Could not authenticate. · Issue #1943 · PHPMailer/PHPMailer · GitHub
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php - How to resolve SMTP could not connect error? [post STARTTLS problem] - Stack Overflow
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php - PHPMailer - SMTP Error: Could not connect to SMTP host - Stack Overflow
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![JENKINS-58813] Cannot send Email notification over office365 smtp with starttls has no effect - Jenkins Jira](https://issues.jenkins.io/secure/attachment/51086/jenkinsError.png "JENKINS-58813] Cannot send Email notification over office365 smtp with starttls has no effect - Jenkins Jira")
JENKINS-58813] Cannot send Email notification over office365 smtp with starttls has no effect - Jenkins Jira
SMTP Error: Could not connect to SMTP host. · Issue #1318 · PHPMailer/PHPMailer · GitHub
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Siva R Vaka: Issues configuring WCM Email notifications with Google SMTP configuration
KB484645: Email delivery fails with error, "STARTTLS is required but host does not support STARTTLS"
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Settings SMTP Email Configuration - Pleasant Solutions
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![[SOLVED] PHPMailer SMTP Error Could not connect to SMTP host - YouTube](https://i.ytimg.com/vi/NjT9FYxj4gw/mqdefault.jpg "[SOLVED] PHPMailer SMTP Error Could not connect to SMTP host - YouTube")